Alkoxy- and Alkyl-Side-Chain-Functionalized Terpolymer Acceptors for All-Polymer Photovoltaics Delivering High Open-Circuit Voltages and Efficiencies

A new terpolymer acceptor is presented, comprising various ratios of the same dithienothienopyrrolobenzothiadiazole (BTP) core with different side chains—alkoxy side chains (BTPO-IC) and alkyl side chains (BTP-IC)—and thiophene units, for use in all-polymer organic photovoltaics. Devices incorporating binary blends of this terpolymer and the polymer PM6 as the active layer displayed open-circuit voltages (V_OC) that increase linearly upon increasing the molar ratio of BTPO-IC. For example, the optimized device incorporating PM6:PY-0.2OBO (i.e., with 20 mol% of BTPO-IC) (1:1.2 wt.%) blend, with the smallest domain sizes but largest coherence length and combined face-on and edge-on orientation fractions among all blends, have a champion power conversion efficiency (PCE) of 16.7% (V_OC = 0.97 V; J_SC = 25.2 mA cm⁻²; FF = 0.68), whereas the device containing a similar blend ratio of the PM6:PY-OD:PY-OBO ternary blend (1:0.96:0.24 wt.%) displayed a PCE of 8.6% (V_OC = 0.969 V; J_SC = 18.7 mA cm⁻²; FF = 0.48). The device with PM6:PY-0.2OBO displays better thermal stability than the devices with PM6: PY-OD or PY-OBO. Thus, employing terpolymer acceptors with differently functionalized side-chain units can be an effective approach for simultaneously optimizing the aggregation domain and enhancing the PCEs and thermal stabilities of all-polymer devices.     

Simultaneously Achieved High Open‐Circuit Voltage and Efficient Charge Generation by Fine‐Tuning Charge‐Transfer Driving Force in Nonfullerene Polymer Solar Cells

To maximize the short‐circuit current density (J_SC) and the open circuit voltage (V_OC) simultaneously is a highly important but challenging issue in organic solar cells (OSCs). In this study, a benzotriazole‐based p‐type polymer (J61) and three benzotriazole‐based nonfullerene small molecule acceptors (BTA1‐3) are chosen to investigate the energetic driving force for the efficient charge transfer. The lowest unoccupied molecular orbital (LUMO) energy levels of small molecule acceptors can be fine‐tuned by modifying the end‐capping units, leading to high V_OC (1.15–1.30 V) of OSCs. Particularly, the LUMO energy level of BTA3 satisfies the criteria for efficient charge generation, which results in a high V_OC of 1.15 V, nearly 65% external quantum efficiency, and a high power conversion efficiency (PCE) of 8.25%. This is one of the highest V_OC in the high‐performance OSCs reported to date. The results imply that it is promising to achieve both high J_SC and V_OC to realize high PCE with the carefully designed nonfullerene acceptors.     

Highly Efficient Ternary Solar Cells with Efficient Förster Resonance Energy Transfer for Simultaneously Enhanced Photovoltaic Parameters

Introducing a third component into organic bulk heterojunction solar cells has become an effective strategy to improve photovoltaic performance. Meanwhile, the rapid development of non-fullerene acceptors (NFAs) has pushed the power conversion efficiency (PCE) of organic solar cells (OSCs) to a higher standard. Herein, a series of fullerene-free ternary solar cells are fabricated based on a wide bandgap acceptor, IDTT-M, together with a wide bandgap donor polymer PM6 and a narrow bandgap NFA Y6. Insights from the morphological and electronic characterizations reveal that IDTT-M has been incorporated into Y6 domains without disrupting its molecular packing and sacrificing its electron mobility and work synergistically with Y6 to regulate the packing pattern of PM6, leading to enhanced hole mobility and suppressed recombination. IDTT-M further functions as an energy-level mediator that increases open-circuit voltage (V_OC) in ternary devices. In addition, efficient Förster resonance energy transfer (FRET) between IDTT-M and Y6 provides a non-radiative pathway for facilitating exciton dissociation and charge collection. As a result, the optimized ternary device features a significantly improved PCE up to 16.63% with simultaneously enhanced short-circuit current (J_SC), V_OC, and fill factor (FF).     

High-Efficiency Organic Solar Cells Enabled by Non-Fullerene Acceptors with Benzimidazole as the Central Core

Electron-deficient central core plays a crucial role in the construction of efficient Y-series non-fullerene acceptors (NFAs). Here, fused-ring benzimidazole (BIm) served as a central core for the first time to yield a new NFA named MZ-1 and its structural analogue named MZ-2, which is obtained by replacing the methyl group on the 2C position of BIm in MZ-1 with trifluoromethyl group. Compared with MZ-1, MZ-2 shows obviously blue-shifted absorption and lowers the highest occupied molecular orbital (HOMO) energy level that is more matched to that of polymer donor PM6. Benefiting from the more efficient charge transport and favorable microphase separation morphology of the active layer, the acceptor MZ-2-based device affords an excellent power conversion efficiency (PCE) of 17.31% along with a high open-circuit voltage (V_oc) of 0.903 V, a short-circuit current density (J_sc) of 26.32 mA cm⁻² and a fill factor (FF) of 72.83%, which is remarkably superior to that of MZ-1-based devices with PCE of 10.70%. This study offers valuable insight into the design of acceptors to enrich Y series NFAs for high-performance organic solar cells (OSCs).     

Relation between morphology and performance parameters of poly(3-hexylthiophene):Phenyl-C61-butyric acid methyl ester photovoltaic devices

Poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) bulk heterojunction (BHJ) solar cells are one of archetypal polymer photovoltaic devices. Understanding the relationship between electronic properties and active layer morphology is essential to obtain high-performance electronic devices. The magnitudes of the short circuit current (J_SC), the fill factor (FF) and the open circuit voltage (V_OC) will vary on the basis of changes in phase purity, interfacial region area and domain size of the active layer. We investigated the device characteristics of the samples having comparable phase purity and found that the performance parameters were better in the device having larger interfacial region area. In another case the phase purity decreases, the interfacial area increases and the recombination rate increases, resulting FF and V_OC increase, J_SC first increases then decreases. Power conversion efficiency (PCE) increases with the increase of interfacial region area, although at the same time associates with the decrease of the phase purity. The device efficiency reaches optimal value by balance the phase purity and the interfacial area. We finally investigated the two devices where, in spite of significant difference between domain dimensions, the PCEs were quite similar. Especially, the devices having large micrometer scale PCBM crystals also obtain good PCEs if they have enough interfacial areas.     

Optimization of interdigitated back contact silicon heterojunction solar cells: tailoring hetero‐interface band structures while maintaining surface passivation

Interdigitated back contact silicon heterojunction (IBC‐SHJ) solar cells have the potential for high open circuit voltage (V_OC) due to the surface passivation and heterojunction contacts, and high short circuit current density (J_SC) due to all back contact design. Intrinsic amorphous silicon (a‐Si:H) buffer layer at the rear surface improve the surface passivation hence V_OC and J_SC, but degrade fill factor (FF) from an “S” shape J–V curve. Two‐dimensional (2D) simulation using “Sentaurus device” demonstrates that the low FF is related to the valence band offset (energy barrier) at the hetero‐interface. Three approaches to the buffer layer are suggested to improve the FF: (1) reduced thickness, (2) increased conductivity, and/or (3) reduced band gap. Experimental IBC‐SHJ solar cells with reduced buffer thickness (<5 nm) and increased conductivity with low boron doping significantly improves FF, consistent with simulation. However, this has only marginal effect on efficiency since J_SC and V_OC also decrease due to poor surface passivation. A narrow band gap a‐Si:H buffer layer improves cell efficiency to 13.5% with unoptimized passivation quality. These results demonstrate that tailoring the hetero‐interface band structure is critical for achieving high FF. Simulations predicts that efficiences >23% are possible on planar devices with optimized pitch dimensions and achievable surface passivation, and 26% with light trapping. This work provides criterion to design IBC‐SHJ solar cell structures and optimize cell performance. Copyright © 2010 John Wiley & Sons, Ltd.     

Small molecule ternary solar cell with two synergistic electron acceptors for enhanced photovoltaic performance

In recent years, tremendous progresses have been achieved for solution processed organic solar cells (OSCs). The strategy of adding a third component to fabricate ternary solar cells has emerged as an effective method to enhance the power conversion efficiency (PCE) of devices. Furthermore, small molecules feature as lower viscosity and excellent repeatability which facilitate the effective morphology control during fabrication process for enhanced photovoltaic performance. Herein, we report a series of ternary solar cells based on a liquid crystal molecule BTR and two electron acceptors of PC₇₁BM and Y6. These molecules show complementary absorption to broaden spectra coverage and form energy levels cascade for efficient charge transfer. Meanwhile, thanks to the improved molecular packing and formed efficient charge transport network in the ternary blend film, the optimal ternary device possesses the improved charge dynamics and suppressed charge recombination. Thus, ternary solar cells deliver the highest PCE of 11.82% with simultaneously enhanced parameters of J_SC, V_OC and FF. This finding further illustrates the important roles of synergistic effect of fullerenes and non-fullerene acceptors in fabricating highly efficient ternary solar cells.     

Regulation of the performance parameters of poly(3-alkylthiophene)/[6,6]-phenyl C61-butyric acid methyl ester solar cells by 1,2,3,4-bis(p-methylbenzylidene) sorbitol

Differential scanning calorimetry (DSC) and atomic force microscopy (AFM) measurements indicate that 1,2,3,4-bis(p-methylbenzylidene) sorbitol (MDBS) is a nucleating agent for both poly(3-alkylthiophene)s (P3ATs) and [6,6]-phenyl C₆₁-butyric acid methyl ester (PCBM), but the intermolecular interaction between P3AT and MDBS is stronger than that between PCBM and MDBS. MDBS regulates the crystallization kinetics of P3AT in P3AT/PCBM blend films, resulting in the acceleration of the crystallization rate, and the decrease of the crystallinity and crystallite size of P3AT. This directly causes the decrease of the open circuit voltage (V_OC) and the increase of both the fill factor (FF) and the short circuit current (J_SC) with the addition of MDBS. Based on the variation of V_OC, FF, and J_SC, the power conversion efficiency (PCE) of P3AT/PCBM BHJ OPV devices improves with the addition of MDBS. Our work verifies that this is a new way to modulate and improve the performance parameters of BHJ OPV devices, i.e., by adding a nucleating agent that modulates the crystallization kinetics of crystalline donor materials.     

A Chlorinated Donor Polymer Achieving High-Performance Organic Solar Cells with a Wide Range of Polymer Molecular Weight

In the field of non-fullerene organic solar cells (OSCs), compared to the rapid development of non-fullerene acceptors, the progress of high-performance donor polymers is relatively slow. The property and performance of donor polymers in OSCs are often sensitive to the molecular weight of the polymers. In this study, a chlorinated donor polymer named D18-Cl is reported, which can achieve high performance with a wide range of polymer molecular weight. The devices based on D18-Cl show a higher open-circuit voltage (V_OC) due to the slightly deeper energy levels and an outstanding short-circuit current density (J_SC) owing to the appropriate long periods of blend films and less ([6,6]-phenyl-C71-butyric acid methyl ester) (PC₇₁BM) in mixed domains, leading to the higher efficiency of 17.97% than those of the D18-based devices (17.21%). Meanwhile, D18-Cl can achieve high efficiencies (17.30–17.97%) when its number-averaged molecular weight (M_n) is ranged from 45 to 72 kDa. In contrast, the D18-based devices only exhibit relatively high efficiencies in a narrow M_n range of ≈70 kDa. Such property and performance make D18-Cl a promising donor polymer for scale-up and low-cost production.     

Fully Printed High-Performance Quasi-Two-Dimensional Perovskite Solar Cells via Multifunctional Interfacial Engineering

Planar n–i–p carbon perovskite solar cells (PSCs) with a hole transport layer that can be fabricated at low temperatures at low-cost exhibit great potential for large-scale manufacturing. Moreover, 2D perovskites have attracted considerable attention owing to their higher stability. In this work, scalable and highly efficient fully printed large-area carbon electrode-based 2D perovskite modules are reported through the insertion of a thin naphthaleneimide derivative (CATNI)-based interfacial layer between tin (IV) oxide and the perovskite layer. The results show that this facilitates the formation of the interfacial contact, suppresses energy losses, and substantially improves the performance parameters of the PSCs, especially their V_OC value. A significantly enhanced V_OC of 1.13 V is achieved resulting in the device PCE value reaching over 18%, which is one of the highest reported for fully printed PSCs so far. It is found that with the deployment of this CATNI-based interfacial layer, a more efficient carrier extraction is achieved. This ultimately contributed to enhanced spectral response as well as improved V_OC for these carbon electrodes based on fully printed devices. Finally, the carbon-perovskite solar modules (carbon-PSMs) are fabricated on ITO glass substrates with dimensions of 5.0 × 5.0 cm. These prepared modules exhibited outstanding photovoltaic performance with the highest PCE value of over 14.6%.     

Influence of aluminium electrode preparation on PCE values of polymeric solar cells based on P3HT and PCBM

The main goal of the paper was investigation of influence of aluminum electrode preparation via thermal evaporation (TE) and the magnetron sputtering (MS) on power conversion efficiency (PCE) of polymeric solar cells. The photovoltaic properties of such three kinds devices based on poly(3-hexylthiophene-2,5-diyl) (P3HT) as ITO/P3HT/Al, ITO/P3HT:PCBM (1:1, w/w)/Al and ITO/PEDOT:PSS/P3HT:PCBM (1:1, w/w)/Al were investigated. For the constructed devices impedance spectroscopy were analyzed. For devices lack of PEDOT:PSS layer or lack of PCBM, photovoltaic parameters were very low and similar to the parameters obtained for device with Al electrode prepared by magnetron sputtering. The devices comprising PEDOT:PSS with P3HT:PCBM showed the best photovoltaic parameters such as a V_OC of 0.60 V, J_SC of 4.61 mA/cm², FF of 0.21, and PCE of 5.7 × 10^?1%.     

Efficient Infrared Solar Cells Employing Quantum Dot Solids with Strong Inter-Dot Coupling and Efficient Passivation

Lead chalcogenide quantum dot (QD) infrared (IR) solar cells are promising devices for breaking through the theoretical efficiency limit of single-junction solar cells by harvesting the low-energy IR photons that cannot be utilized by common devices. However, the device performance of QD IR photovoltaic is limited by the restrictive relation between open-circuit voltages (V_OC) and short circuit current densities (J_SC), caused by the contradiction between surface passivation and electronic coupling of QD solids. Here, a strategy is developed to decouple this restriction via epitaxially coating a thin PbS shell over the PbSe QDs (PbSe/PbS QDs) combined with in situ halide passivation. The strong electronic coupling from the PbSe core gives rise to significant carrier delocalization, which guarantees effective carrier transport. Benefited from the protection of PbS shell and in situ halide passivation, excellent trap-state control of QDs is eventually achieved after the ligand exchange. By a fine control of the PbS shell thickness, outstanding IR J_SC of 6.38 mA cm⁻² and IR V_OC of 0.347 V are simultaneously achieved under the 1100 nm-filtered solar illumination, providing a new route to unfreeze the trade-off between V_OC and J_SC limited by the photoactive layer with a given bandgap.     

Efficient bulk heterjunction solar cells based on a low-bandgap polyfluorene copolymers and fullerene derivatives

A low-bandgap polymer (PF-PThCVPTZ) consisted of fluorene and phenothiazine was designed and synthesized. With the donor–acceptor segment, the partial charge transfer can be built in the polymer backbone leading to a wide absorbance. The absorption spectrum of PF-PThCVPTZ exhibits a peak at 510 nm and an absorption onset at 645 nm in the visible range. As blended with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) as an electron acceptor, narrow bandgap PF-PThCVPTZ as electron donor shows significant solar cell performance. Under AM 1.5 G, 100 mA/cm² illumination, a power conversion efficiency (PCE) of 1.85% was recorded, with a short circuit current (J_SC) of 5.37 mA/cm², an open circuit voltage (V_OC) of 0.80 V, and a fill factor (FF) of 43.0%.     

High-Performance Ternary Organic Solar Cells Enabled by Integrating a 3D-Shaped Guest Acceptor Derived from Perylene Diimide

Integrating a third component into the binary system is considered to be one of the most effective strategies to further enhance the power conversion efficiency (PCE) in organic solar cells (OSCs). Here, a novel perylene diimide (PDI) derivative featuring 3D structure, TPA-4PDI, with tetraphenyladamantane central core is developed as a guest electron acceptor to be incorporated into the PM6:Y6 binary system. The champion PCE of ternary OSC is recorded to be 18.29% by adding 7.5 wt.% of TPA-4PDI in the ternary blend, which photovoltaic performance is enhanced with synergistically increased open-circuit voltage (V_oc) of 0.849 V, short-circuit current density (J_sc) of 27.55 mA cm⁻², and fill factor (FF) of 78.21%. TPA-4PDI exhibits a complementary absorption band with PM6 and Y6 while its lowest unoccupied molecular orbital (LUMO) energy level falls between the two host materials. The addition of TPA-4PDI can effectively suppress the recombination behavior, inhibit the excessive aggregation of Y6 and improve the morphology of PM6:Y6 blend. All these effects function synergistically and then lead to the enhancement of V_oc, J_sc, and FF in ternary OSCs. This study suggests that developing PDI derivatives as the third component is an effective method to further improve the performance of ternary OSCs.     

Revealing the effect of donor/acceptor intermolecular arrangement on organic solar cells performance based on two-dimensional conjugated small molecule as electron donor

A series of solution processed organic solar cells (OSCs) were fabricated with a two-dimensional conjugated small molecule SMPV1 as electron donor and fullerene derivatives PC₇₁BM or ICBA as electron acceptor. The champion power conversion efficiency (PCE) of OSCs arrives to 7.05% for the cells with PC₇₁BM as electron acceptor. A relatively large open circuit voltage (V_OC) of 1.15 V is obtained from cells using ICBA as electron acceptor with an acceptable PCE of 2.54%. The fill factor (FF) of OSCs is 72% or 61% for the cells with PC₇₁BM or ICBA as electron acceptor, which is relatively high value for small molecule OSCs. The relatively low performance of OSCs with ICBA as electron acceptor indicates that ICBA cannot play positive role in photoelectric conversion processes, which is very similar to the phenomenon observed from the OSCs with high efficient narrow band gap polymers other than P3HT as electron donor, the underlying reason is still in debate. The SMPV1 has strong self-assemble ability to form an ordered two dimensional lamellar structure, which provides an effective platform to investigate the effect of electron acceptor chemical structure on the performance of OSCs. Experimental results exhibit that ICBA molecules may prefer to vertical cross-intercalation among side chains of SMPV1, PC₇₁BM molecules may have better miscibility with SMPV1 in the active layer. The different donor/acceptor (D/A) intermolecular arrangement strongly influences photon harvesting, exciton dissociation and charge carrier transport, which may provide a new sight on performance improvement of OSCs by adjusting D/A intermolecular arrangements.     

Recent progress in high efficiency polymer solar cells by rational design and energy level tuning of low bandgap copolymers with various electron-withdrawing units

AbstractThis review collects recent five-year publications on low bandgap semiconducting polymers, which are composed of electron donor (D) and electron acceptor (A) units, exhibiting the power conversion efficiency (PCE) higher than 6%. When the photovoltaic performances of different types of D−A semiconducting copolymers are compared after the copolymers are classified into several categories according to the type of A-units, it is realized that diketopyrrolopyrrole (DPP)-based copolymers exhibit high J_SCs owing to low bandgaps and low V_OCs due to high-lying HOMO levels, while thienopyrroledione (TPD)-based copolymers exhibit high V_OCs due to their deep HOMO levels and low J_SCs because of wide bandgaps. Benzothiadiazole- and thienothiophene-based copolymers show intermediate values of V_OC and J_SC between DPP- and TPD-based ones. For further enhancement of photovoltaic performance, DPP-based copolymers may be designed to have deeper HOMO level with the minimum widening of bandgap while TPD-based polymers may be designed to have lower bandgap with the minimum rise of HOMO level. Hence, the energy level tuning must be considered so as to minimize the adverse effect.     

Suppressing the Photoinduced Halide Segregation in Wide-Bandgap Perovskite Solar Cells by Strain Relaxation

Efficient and stable wide bandgap (WBG) perovskite solar cells (PSCs) are imperative for fabricating superior tandem devices. However, small crystal grains and light-induced phase segregation of WBG perovskite result in large open-circuit voltage (V_OC) deficits, critically impeding the development of the related devices. Herein, the effective functional groups of Lewis-base trans-Ferulic acid (t-FA) are employed to release the residual microstrain in the perovskite lattice. Larger perovskite crystals are formed by strengthening the interaction between the perovskite solute and solution. The lattice structure is stabilized to suppress light-induced halide segregation. Finally, the power conversion efficiency (PCE) of the optimized device with a bandgap of ≈1.77 eV is increased from 17.33% to 19.31% with the enhancement of V_OC. Moreover, replacing a mixture of MeO-2PACZ and Me-4PACZ as the hole transporting layer (HTL), the PCE further lifts to 19.9% and V_OC is 1.32 V, one of the highest performances reported for WBG PSCs, especially for devices prepared entirely by solution spin-coating. Therefore, this study provides a practicable alternative for realizing efficient WBG PSCs, which can contribute to the growth of perovskite-based tandem devices.     

Fused-ring acceptors based on quinoxaline unit for highly efficient single-junction organic solar cells with low charge recombination

Two non-fullerene small molecule acceptors (TFQ-F and TFQ-Cl) based on quinoxaline unit were designed and synthesized for efficient organic solar cells (OSCs). These two acceptors showed intense absorption up to 900 nm and high thermal stabilities with decomposition temperatures over 360 °C due to their fused-ring skeletons. TFQ-F and TFQ-Cl are the A-D-A′-D-A type acceptors (A/A′ for acceptor unit and D for donor unit). TFQ-F and TFQ-Cl have the same D-A′-D fragment, which was flanked with different ending groups. The effect of different ending groups on their photophysical properties, electrochemical behaviors, micro-structures and charge recombination properties of active layers, and device performance were investigated systematically. PM6 with the complementary absorption to the two acceptors was used as the donor material. The pristine PM6:TFQ-F blend films displayed the optimal morphologies as revealed by AFM and TEM measurement. Organic solar cells based on PM6:TFQ-Cl blend film showed high J_SC of 25.19 mA/cm² and PCE of 13.2%. The Voc, J_SC and PCE for PM6:TFQ-F film based device were 0.857 V, 23.70 mA/cm² and 13.51%, respectively. The dependence of V_OC/J_SC on various light intensities indicated that PM6:TFQ-F/Cl based device had low charge recombination.     

Effects of functionalization of Y6 end-groups with electron-withdrawing groups on the photovoltaic properties at the donor-acceptor interfaces of PM6/Y6 OSCs: A theoretical insight

Since the high performance non-fullerene acceptor Y6 appears, many organic solar cells (OSCs) based on it and its derivatives have been fabricated and studied. These OSCs show delicate changes of open circuit voltage (V_OC), short circuit density (J_SC), and fill factor (FF) with respect to prototype PM6/Y6 OSC. So far, the effects of functionalization of Y6 end-groups with electron-withdrawing groups on the photovoltaic properties at the donor-acceptor interfaces of PM6/Y6 OSC are still not well understood. In the present work, by modelling four OSCs based on symmetrical (Y6, Y6-4Cl, and Y6-4CN) and asymmetrical (Y6-2Cl) molecules, we find that for symmetrical Y6 and Y6-4Cl based OSCs, the computed V_OCs and FFs obtained with reliable computational method show the same trend as experimental data, but the computational method used does not apply for asymmetrical Y6-2Cl based OSC. In addition, with respect to fluorination, chlorination generally would bring stronger simulated interfacial absorption spectrum, the smaller exciton binding energy of local excited state of monomers and charge transfer state at the interface, smaller singlet−triplet energy gap, the higher total oscillator strength of all CT states, and larger interfacial electrostatic potential difference. In contrast, PM6/Y6-4CN has relative much lower total oscillator strength of all CT states and predicted V_OC and FF than prototype Y6/PM6 though the end-groups with CN substitutions have much stronger electron withdrawing ability. Our results gain insights into the donor-acceptor interfacial properties of OSCs based on Y6 and its derivatives.     

Understanding Temperature‐Dependent Charge Extraction and Trapping in Perovskite Solar Cells

Understanding the factors that limit the performance of perovskite solar cells (PSCs) can be enriched by detailed temperature (T)‐dependent studies. Based on p‐i‐n type PSCs with prototype methylammonium lead triiodide (MAPbI₃) perovskite absorbers, T‐dependent photovoltaic properties are explored and negative T‐coefficients for the three device parameters (V_OC, J_SC, and FF) are observed within a wide low T‐range, leading to a maximum power conversion efficiency (PCE) of 21.4% with an impressive fill factor (FF) approaching 82% at 220 K. These T‐behaviors are explained by the enhanced interfacial charge transfer, reduced charge trapping with suppressed nonradiative recombination and narrowed optical bandgap at lower T. By comparing the T‐dependent device behaviors based on MAPbI₃ devices containing a PASP passivation layer, enhanced PCE at room temperature is observed but different tendencies showing attenuating T‐dependencies of J_SC and FF, which eventually leads to nearly T‐invariable PCEs. These results indicate that charge extraction with the utilized all‐organic charge transporting layers is not a limiting factor for low‐T device operation, meanwhile the trap passivation layer of choice can play a role in the T‐dependent photovoltaic properties and thus needs to be considered for PSCs operating in a temperature‐variable environment.