New Polymerized Small Molecular Acceptors with Non-Aromatic π-Conjugated Linkers for Efficient All-Polymer Solar Cells

Developing new polymerized small molecular acceptor (PSMA) is pivotal for improving the performance of all-polymer solar cells. On the basis of this newly developed CH-series small molecule acceptors, two PSMAs are reported herein (namely PZC16 and PZC17, respectively). To reduce the molecular torsion caused by the traditional aromatic π-bridges, non-aromatic conjugated units (ethynyl for PZC16 and vinylene for PZC17) are adopted as the linkers and their effect on the photo-physical properties as well as the device performance are systematically investigated. Both polymer acceptors exhibit co-planar molecular conformation, along with broad absorption ranges and suitable energy levels. In comparison with the PM6:PZC16 film, the PM6:PZC17 film exhibits more uniform phase separation in morphology with a distinct bi-continuous network and better crystallinity. The PM6:PZC17-binary-based devices exhibit a satisfactory PCE of 16.33%, significantly higher than 9.22% of the PZC16-based devices. Impressively, PM6:PZC17-based large area device (ca. 1 cm²) achieves an excellent PCE of 15.14%, which is among the top performance for reported all-polymer solar cells (all-PSCs).     

High-Efficiency Organic Solar Cells Based on a Low-Cost Fully Non-Fused Electron Acceptor

A series of tetrathiophene-based fully non-fused ring acceptors (4T-1, 4T-2, 4T-3, and 4T-4), which can be paired with the star donor polymer PBDB-T to fabricate highly efficient organic solar cells are developed. Tailoring the size of lateral chains can tune the solubility and packing mode of acceptor molecules in neat and blend films. It is found that the incorporation of 2-ethylhexyl chains can effectively change the compatibility with the donor polymer PBDB-T, and an encouraging power conversion efficiency of 10.15% is accomplished by 4T-3-based organic solar cells. It also presents good compatibility with the other polymer donor and an even higher power conversion efficiency (PCE) of 12.04% is achieved based on D18:4T-3 blend, which is the champion PCE for the fully non-fused acceptors. Importantly, these inexpensive tetrathiophene fully non-fused ring acceptors provide cost-effective photovoltaic performance. The results demonstrate a high photovoltaic performance from synthetically inexpensive materials could be achieved by the rational design of non-fused ring acceptor molecules.     

Poly(2,2’-(2,5-difluoro-1,4-phenylene)dithiophene-alt-naphthalene diimide) synthesized by direct (hetero)arylation reaction for all-polymer solar cells

The weak donor-strong acceptor polymer acceptors for all-polymer solar cells (all-PSCs) have gained much less attention compared with the typical donor-strong acceptor counterparts. Direct (hetero)arylation polymerization reaction is a rising synthetic method, although most of the naphthalene diimide polymer photovoltaic acceptors have been prepared by classic Stille polymerization. A weak donor-strong acceptor polymer acceptor PNB2F has been successfully designed and synthesized by the two-step direct (hetero)arylation reaction and further applied in all-PSCs. The all-PSC device based on PNB2F and electron-donating polymer PBDB-T gained a PCE of 4.49%. The results demonstrate that direct (hetero)arylation reaction is a promising tool for building efficient polymer acceptors with convenient and low-cost synthesis ideas.     

Highly Efficient Ternary All-Polymer Solar Cells with Enhanced Stability

Developing organic solar cells (OSCs) based on a ternary active layer is one of the most effective approaches to maximize light harvesting and improve their photovoltaic performance. However, this strategy meets very limited success in all-polymer solar cells (all-PSCs) due to the scarcity of narrow bandgap polymer acceptors and the challenge of morphology optimization. In fact, the power conversion efficiencies (PCEs) of ternary all-PSCs even lag behind binary all-PSCs. Herein, highly efficient ternary all-PSCs are realized based on an ultranarrow bandgap (ultra-NBG) polymer acceptor DCNBT-TPC, a medium bandgap polymer donor PTB7-Th, and a wide bandgap polymer donor PBDB-T. The optimized ternary all-PSCs yield an excellent PCE of 12.1% with a remarkable short-circuit current density of 21.9 mA cm⁻². In fact, this PCE is the highest value reported for ternary all-PSCs and is much higher than those of the corresponding binary all-PSCs. Moreover, the optimized ternary all-PSCs show a photostability with ≈ 68% of the initial PCE retained after 400 h illumination, which is more stable than the binary all-PSCs. This work demonstrates that the utilization of a ternary all-polymer system based on ultra-NBG polymer acceptor blended with compatible polymer donors is an effective strategy to advance the field of all-PSCs.     

Efficient ternary polymer solar cells by optimizing photogenerated exciton dissociation and photon harvesting with a short wavelength absorption polymer acceptor as the third component

Ternary blend films, obtained by introducing a third component (a second acceptor as the third component) to a binary polymer solar cell (PSC), are a promising ternary strategy because the light absorption range, surface morphology, and charge carrier transport of the photoactive layer may be optimized, as can the energy level alignment between the donor and the acceptor. In this work, acceptors such as the short-wavelength-absorption polymer N2200 and the long-wavelength-absorption small molecule FOIC were combined with the donor PBDB-T-2F to construct ternary blends. The optimized ternary PSC could achieve a power conversion efficiency (PCE) of 13.98%, which is higher than the efficiencies of binary PSCs based on PBDB-T-2F:FOIC (12.65%) and PBDB-T-2F:N2200 (9.36%). The enhanced PCE of the ternary PSC is based on the high electron mobility, balanced charge transport, optimized surface morphology and charge carrier kinetics and the extended light absorption of the ternary photoactive layer, realized by adjusting the ratio of FOIC:N2200. Our results indicate that mixing a polymer acceptor into a binary photoactive layer to form a ternary blend photoactive layer is a valuable strategy for improving photovoltaic performance.     

Synthesis and photovoltaic performance of a non-fullerene acceptor comprising siloxane-terminated alkoxyl side chain

As an effective molecular modification strategy, side chain engineering has been widely used in promoting the photovoltaic performance of non-fullerene acceptors. Herein, a novel non-fullerene small molecular acceptor i-IEOSi-4F comprising siloxane-terminated alkoxyl side chain was successfully designed and synthesized. The molecule shows an optical band gap of 1.53 eV, with large extinction coefficient of 2.36 × 10⁵ M⁻¹ cm⁻¹ in solution. Two fluorobenzotriazole based polymers J52 and PBZ-2Si with the same backbone units but different side chains were employed as the donor to construct the active layers that all can demonstrate suitable energy levels and complementary absorptions with i-IEOSi-4F. Relative to J52 only bearing alkyl side chain, PBZ-2Si with siloxane-terminated side chain could induce more balanced carrier transports and more favorable morphology, leading to a higher power conversion efficiency (PCE) of 12.66% with a good fill factor of 71.45%. The efficiency is 21% higher than that of 10.46% for the J52 based devices. Our results not only indicate that siloxane-terminated alkoxyl side chain is valuable for efficient non-fullerene acceptors, but also demonstrate that siloxane-terminated side chain on both polymer donor and small molecular acceptor is a useful combination to realize more efficient polymer solar cells.     

Twisted donor substituted simple thiophene dyes retard the dye aggregation and charge recombination in dye-sensitized solar cells

Two novel thiophene 3,4-disubstituted organic dyes with double acceptors at 2,5-position framework photosensitizers were carefully designed and synthesized for the dye sensitized solar cell (DSSC) application. In this submission, the influence of carbazole (Cz) and triphenylaime (NPh3) units substitution at 3,4-position of thiophene is studied. Both the planar structure of carbazole based dyes and three dimension structure of triphenylamine based dyes are found to effectively inhibit the I⁻/I₃⁻ and Co⁺²/Co⁺³ electrolyte on TiO₂ surface. The results show that varying the donor position in dyes also effectively works for DSSC application, even if it does not broaden the absorption peak in visible region (for both the dyes) due to the blocking of electron delocalization at 2,5-positions by acceptor units. With two twisted donors at 3,4-position in Cz-Th-Dye, NPh3-Th-Dye the dye aggregation and charge recombination retarded. The optical, electrochemical, density functional theory and TRPL studies were used to estimate the photovoltaic properties of the dyes. The dye having two acceptors on both sides (2,5-position) of thiophene moiety showed efficient electron extraction from the electron donor part. Without using any additives, Cz-Th dye and NPh3-Th dye in presence of cobalt (II/III) redox shuttle, resulted in the power conversion efficiency (η, PCE) of ∼3.4% and 3.1% respectively. By replacing one acceptor with any other donor, these thiophene moiety can effectively work as a new π-spacer in DSSC application.     

Rational design of perylenediimide-based polymer acceptor for efficient all-polymer solar cells

Perylenediimide (PDI)-based small molecules have significantly contributed to the development of non-fullerene acceptors, whereas the development of PDI-based polymer acceptors is relatively lagging behind. In this study, we designed and synthesized two PDI-based n-type polymers named as PF-PDI and PBDT-PDI, in which PDI was used as electron-deficient unit and fluorene (F) or benzodithiophene (BDT) were used as electronrich components. The density functional theory (DFT) calculations and grazing incidence wide-angle X-ray scattering (GIWAXS) results indicate that the PF-PDI shows larger steric hindrance and relatively weaker lamellar packing than that of PBDT-PDI. Comparing with PBDT-PDI, PF-PDI shows red-shift absorption and lower-lying HOMO level, which agrees well with the DFT results. A well-known wide bandgap polymer donor, PDBT-T1 was employed to fabricate polymer solar cells (PSCs) with the two acceptors. The all polymer solar cells (all-PSCs) based on PDBT-T1:PF-PDI showed a high power conversion efficiency (PCE) of 4.47%, which is approximately 2-fold larger than that of devices with PDBT-T1:PBDT-PDI (PCE = 2.70%).     

Fibril Network Strategy Enables High‐Performance Semitransparent Organic Solar Cells

The development of semitransparent organic solar cells (ST‐OSCs) represents a significant step toward the commercialization of OSCs. However, the trade‐off between power conversion efficiency (PCE) and average visible transmittance (AVT) restricts further improvements of ST‐OSCs. Herein, it is demonstrated that a fibril network strategy can enable ST‐OSCs with a high PCE and AVT simultaneously. A wide‐bandgap polymer PBT1‐C‐2Cl that can self‐assemble into a fibril nanostructure is used as the donor and a near‐infrared small molecule Y6 is adopted as the acceptor. It is found that a tiny amount of PBT1‐C‐2Cl in the blend can form a high speed pathway for hole transport due to the well distributed fibril nanostructure, which increases the transmittance in the visible region. Meanwhile, the acceptor Y6 guarantees sufficient light absorption. Using this strategy, the optimized ST‐OSCs yield a high PCE of 9.1% with an AVT of over 40% and significant light utilization efficiency of 3.65% at donor/acceptor ratio of 0.25:1. This work demonstrates a simple and effective approach to realizing high PCE and AVT of ST‐OSCs simultaneously.     

Unconjugated Side‐Chain Engineering Enables Small Molecular Acceptors for Highly Efficient Non‐Fullerene Organic Solar Cells: Insights into the Fine‐Tuning of Acceptor Properties and Micromorphology

2D conjugated side‐chain engineering is an effective strategy that is widely utilized to construct benzodithiophene‐based polymers. Herein, an unconjugated side‐chain strategy to design fused‐benzodithiophene‐based non‐fullerene small molecule acceptors (SMAs) via vertical aromatic side‐chain engineering on the ladder‐type core is employed. Three SMAs named BTTIC‐Th, BTTIC‐TT, and BTTIC‐Ph with thiophene, thieno[3,2‐b]thiophene, and benzene, respectively, as side chains, are designed and synthesized. Three SMAs exhibit similar absorption ranges but different lowest unoccupied molecular orbital (LUMO) energy levels due to the different strength of the δ‐inductive effect between vertical aromatic side chains and their electron‐rich core. Organic solar cells based on PBDB‐T:BTTIC‐TT achieve a power conversion efficiency (PCE) of 13.44%, which is higher than the PCE of devices based on PBDB‐T:BTTIC‐Th (12.91%) and PBDB‐T:BTTIC‐Ph (9.14%). The difference in device performance is investigated by electrical and morphological characterizations. A large domain size and different types of π–π stacking are found in the bulk heterojunction layer of PBDB‐T:BTTIC‐Ph blend film, which are detrimental to exciton dissociation and charge transport. Overall, it is demonstrated that when designing unconjugated side chains, thieno[3,2‐b]thiophene is superior to thiophene and benzene through its dual roles of promoting the LUMO energy level and optimizing the morphology. These results shed light on the side‐chain engineering of high‐performance non‐fullerene SMAs.     

Ternary Blend Strategy for Achieving High‐Efficiency Organic Solar Cells with Nonfullerene Acceptors Involved

Nonfullerene acceptors have recently drawn considerable attention in bulk heterojunction organic solar cells (OSCs). The power conversion efficiency (PCE) over 14% is achieved in single‐junction fullerene‐free OSCs, which has surpassed that of fullerene‐based counterparts. For future commercial applications, however, a high and stable PCE > 15% is required, which entails rational material design and device optimization. In this context, three approaches are generally utilized—the synthesis of novel nonfullerene acceptors and the selection of suitable polymer donors to pair with them, the tandem or multijunction device architecture, and the ternary blend strategy. Compared to the former two methods, the ternary strategy allows to employ the existing photovoltaic materials and the single‐junction device. Therefore, an exploration of nonfullerene acceptor–based ternary blend OSCs (NFTSCs) has shown unprecedented progress since 2016. This review summarizes and classifies the photovoltaic materials utilized in NFTSCs, aiming to not only exhibit the recent development of NFTSCs but also elucidate the correlation among donor/acceptor materials, film morphology, transport dynamics, and device fabrication toward high‐efficiency OSCs. Lastly, the above key advances are highlighted along with the existing issues and insights into the viable path for the further research thrusts are offered.     

Donor–acceptor copolymers based on benzo[1,2-b:4,5-b′]dithiophene and pyrene-fused phenazine for high-performance polymer solar cells

Two novel donor–acceptor (D–A)-type conjugated polymers of PTTPPz-BDT and PTTPPz-BDTT were successfully synthesized by Stille coupling polymerization, in which 7,8-dialkoxy benzo[1,2-b:4,5-b′]dithiophene (BDT) and 7,8-bithienyl benzo[1,2-b:4,5-b′]dithiophene (BDTT) were used as donor units, thiophene and pyrene-fused phenazine (PPz) were employed as π-bridges and acceptor units, respectively. High carrier mobilities, broad absorption spectra, narrow optical band gaps, and low HOMO energy levels were observed for both polymers. Furthermore, high-efficiency photovoltaic performance with power conversion efficiency (PCE) over 4.25% was exhibited in their polymer solar cells (PSCs) using [6,6]-phenyl-C₇₁-butyric-acid-methyl-ester (PC₇₁BM) as acceptor. The maximum PCE of 4.86% with short-circuit current density of 11.10 mA cm⁻² and fill factor of 62.5% was obtained in the PTTPPz-BDTT based cell. These results indicate that incorporating large planar PPz moiety into D–A-type copolymer is an efficient approach to improve photovoltaic performance for PSCs.     

Fused Cyclopentadithienothiophene Acceptor Enables Ultrahigh Short‐Circuit Current and High Efficiency >11% in As‐Cast Organic Solar Cells

A new method to synthesize an electron‐rich building block cyclopentadithienothiophene (9H‐thieno‐[3,2‐b]thieno[2″,3″:4′,5′]thieno[2′,3′:3,4]cyclopenta[1,2‐d]thiophene, CDTT) via a facile aromatic extension strategy is reported. By combining CDTT with 1,1‐dicyanomethylene‐3‐indanone endgroups, a promising nonfullerene small molecule acceptor (CDTTIC) is prepared. As‐cast, single‐junction nonfullerene organic solar cells based on PFBDB‐T: CDTTIC blends exhibit very high short‐circuit currents up to 26.2 mA cm^?2 in combination with power conversion efficiencies over 11% without any additional processing treatments. The high photocurrent results from the near‐infrared absorption of the CDTTIC acceptor and the well‐intermixed blend morphology of polymer donor PFBDB‐T and CDTTIC. This work demonstrates a useful fused ring extension strategy and promising solar cell results, indicating the great potential of the CDTT derivatives as electron‐rich building blocks for constructing high‐performance small molecule acceptors in organic solar cells.     

Fullerene Adducts Bearing Cyano Moiety for Both High Dielectric Constant and Good Active Layer Morphology of Organic Photovoltaics

Power conversion efficiency (PCE) of organic photovoltaics (OPVs) lags behind of inorganic photovoltaics due to low dielectric constants (ε _r) of organic semiconductors. Although OPVs with high ε _r are attractive in theory, practical demonstration of efficient OPV devices with high‐ε _r materials is in its infancy. This is largely due to the contradiction between the requirements of high ε _r and good donor:acceptor blend morphology in the bulk heterojunction. Herein, a series of fullerene acceptors is reported bearing a polar cyano moiety for both high ε _r and good donor:acceptor blend morphology. These cyano‐functionalized acceptors (ε _r = 4.9) have higher ε _r than that of the widely used acceptor, [6,6]‐phenyl‐C₆₁‐butyric acid methyl ester (PC₆₁BM) (ε _r = 3.9). The high ε _r is realized without decrease of electron mobility and change of the lowest unoccupied molecular orbital/highest occupied molecular orbital (LUMO/HOMO) energy levels. Although the cyano‐functionalized acceptors have increased polarity, they still exhibit good compatibility with the typical donor polymer. Polymer solar cells based on the cyano‐functionalized acceptors exhibit good active layer morphology and show better device performance (PCE = 5.55%) than that of PC₆₁BM (PCE = 4.56%).     

Synthesis and Structure–Property Correlations of Dicyanovinyl‐Substituted Oligoselenophenes and their Application in Organic Solar Cells

The convergent synthesis of a series of acceptor–donor–acceptor (A‐D‐A) type dicaynovinyl (DCV)‐substituted oligoselenophenes DCVnS (n = 3–5) is presented. Trends in thermal and optoelectronic properties are studied, in dependence on the length of the conjugated backbone. Optical measurements reveal red‐shifted absorption spectra and electrochemical investigations show lowering of the lowest unoccupied molecular orbital (LUMO) energy levels for DCVnS compared to the corresponding thiophene analogs DCVnT. As a consequence, a lowering of the bandgap is observed. Single crystal X‐ray structure analysis of tetramer DCV4S provides important insight into the packing features and intermolecular interactions of the molecules, further corroborating the importance of the DCV acceptor groups for the molecular ordering. DCV4S and DCV5S are used as donor materials in planar heterojunction (PHJ) and bulk‐heterojunction (BHJ) organic solar cells. The devices show very high fill factors (FF), a high open circuit voltage, and power conversion efficiencies (PCE) of up to 3.4% in PHJ solar cells and slightly reduced PCEs of up to 2.6% in BHJ solar cells. In PHJ devices, the PCE for DCV4S almost doubles compared to the PCE reported for the oligothiophene analog DCV4T, while DCV5S shows an about 30% higher PCE than DCV5T.     

Conjugated dendritic oligothiophenes for solution-processed bulk heterojunction solar cells

This mini-review summarizes the recent achievements of developing conjugated dendritic oligothiophenes (DOT) for use in solution-processed bulk heterojunction (BHJ) solar cells. These DOTs are structurally defined molecules with relatively high molecular weight. Therefore, this novel class of thiophene based material possesses not only some advantages of oligomers,such as defined and monodispersed molecular structure,high chemical purity, but also some characteristics of polymers, for example, good solution-processability.In addition, the step-by-step approach of its synthesis allows precise fimctionalization of dendritic backbones with desired moieties, which is helpful to finely tune the optical and electronic properties of materials. Power conversion efficiencies (PCE) of BHJ solar cells were achieved up to 2.5% when functionalized thiophene dendrimers were used as electron donor and electron acceptor was a fullerene derivative. These results indicated that dendritic oligothiophenes are a novel class of the materials of electron donor for solution-processed organic solar cells.     

Imide‐Functionalized Heteroarene‐Based n‐Type Terpolymers Incorporating Intramolecular Noncovalent Sulfur∙∙∙Oxygen Interactions for Additive‐Free All‐Polymer Solar Cells

The aggregation/crystallinity of classic n‐type terpolymers based on naphthalene diimide and perylene diimide is challenging to tune due to their rigid and extended cores, leading to suboptimal film morphology. A new strategy for developing high‐performance n‐type terpolymers by incorporating imide‐functionalized heteroarenes is reported here to balance crystallinity and miscibility without sacrificing charge carrier mobilities. The introduction of thienopyrroledione (TPD) into the copolymer f‐BTI2‐FT results in a series of terpolymers BTI2‐xTPD having distinct TPD content. The irregular backbone reduces crystallinity, yielding improved miscibility with the polymer donor. More importantly, TPD triggers noncovalent S?O interactions, increasing backbone planarity and in‐chain charge transport. Such interactions also promote face‐on polymer packing. As a result, all‐polymer solar cells (all‐PSCs) based on BTI2‐30TPD achieve an optimal power conversion efficiency (PCE) of 8.28% with a small energy loss (0.53 eV). This efficiency is substantially higher than that of TPD (4.4%) or a BTI2‐based copolymer (6.8%) and is also the highest for additive‐free all‐PSCs based on a terpolymer acceptor. Moreover, the BTI2‐30TPD cell exhibits excellent stability with the PCE retaining 90% of its initial value after 400 h of aging. The results demonstrate that random polymerization using imide‐functionalized heteroarenes is a powerful approach to develop terpolymer acceptors toward efficient and stable all‐polymer solar cell PSCs.     

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.     

Rational Design of Small Molecular Donor for Solution‐Processed Organic Photovoltaics with 8.1% Efficiency and High Fill Factor via Multiple Fluorine Substituents and Thiophene Bridge

A series of tetrafluorine‐substituted small molecules with a D₁‐A‐D₂‐A‐D₁ linear framework based on indacenodithiophene and difluorobenzothiadiazole is designed and synthesized for application as donor materials in solution‐processed small‐molecule organic solar cells. The impacts of thiophene π‐bridge and multiple fluorinated modules on the photophysical properties, the energy levels of the highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO), charge carrier mobility, the morphologies of blend films, and their photovoltaic properties as electron donor material in the photoactive layer are investigated. By incorporating multiple fluorine substituents of benzothiadiazole and inserting two thiophene spacers, the fill factor (FF), open‐circuit voltage, and short‐circuit current density are dramatically improved in comparison with fluorinated‐free materials. With the solvent vapor annealing treatment, further enhancement in charge carrier mobility and power conversion efficiency (PCE) are achieved. Finally, a high PCE of 8.1% with very‐high FF of 0.76 for BIT‐4F‐ T/PC₇₁BM is achieved without additional additive, which is among one of the highest reported for small‐molecules‐based solar cells with PCE over 8%. The results reported here clearly indicate that high PCE in solar cells based small molecules can be significantly increased through careful engineering of the molecular structure and optimization on the morphology of blend films by solvent vapor annealing.     

The investigations of two conjugated polymers that show distinctly different photovoltaic properties in polymer solar cells

In fullerene-free polymer solar cells (PSC), the non-fullerene small molecular acceptors (NF-SM) demonstrates quite different film morphology in comparison with the conventional fullerene acceptors when blended with the same conjugated polymer donor. In this work, a NF-SM acceptor, ITIC, was introduced into two efficient binary PSCs based on fullerene to fabricate ternary solar cells. It is found that the addition of ITIC led fundamentally different results. After carefully investigated the difference on film morphology and charge carriers' mobility, the results showed that the good miscibility between ITIC and the polymer may deteriorate the favorable film morphology with appropriate phase separation and suppress the formation of continues charge transport channel. This work offered a useful consideration to produce high-performance ternary PSCs by rational selecting the donors and acceptors.