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1.
Two molecules denoted as VC96 and VC97 have been synthesized for efficient (η = 6.13% @ 100 mW/cm2 sun-simulated light) small molecule solution processed organic solar cells. These molecules have been designed with the D1-A-D2-A-D1 structure bearing different central donor unit, same benzothiadiazole (BT) as π-acceptor and end capping triphenylamine. Moreover, the optical and electrochemical properties (both experimental and theoretical) of these molecules have been systematically investigated. The solar cells prepared from VC96:PC71BM and VC97:PC71BM (1:2) processed from CF (chloroform) exhibit a PCE (power conversion efficiency) of η = 4.06% (Jsc = 8.36 mA/cm2, Voc = 0.90 V and FF = 0.54) and η = 3.12% (Jsc = 6.78 mA/cm2, Voc = 0.92 V and FF = 0.50), respectively. The higher PCE of the device with VC96 as compared to VC97 is demonstrated to be due to the higher hole mobility and broader IPCE spectra. The devices based on VC96:PC71BM and VC97:PC71BM processed with solvent additive (3 v% DIO, 1,8-diiodooctane) showed PCE of η = 5.44% and η = 4.72%, respectively. The PCE device of optimized VC96:PC71BM processed with DIO/CF (thermal annealed) has been improved up to 6.13% (Jsc = 10.72 mA/cm2, Voc = 0.88 V and FF = 0.61). The device optimization results from the improvement of the balanced charge transport and better nanoscale morphology induced by the solvent additive plus the thermal annealing.  相似文献   

2.
In this work, we present vacuum-deposited bifacial transparent organic solar cells on indium-tin-oxide-coated glass substrates. Good performances and high transparencies are achieved simultaneously by employing the planar-mixed heterojunction of the organic donor 2-{[7-(5-N,N-ditolylaminothiophen-2-yl)-2,1,3-benzothiadiazol-4-yl]methylene}malononitrile (DTDCTB) and fullerenes with carefully designed resonance top electrodes. Comprehensive optical simulation is exploited to investigate the effect of the top-electrode configuration on the cell transparency and efficiency. Cells with structures designed for high transparencies were fabricated and tested. The DTDCTB:C60 device yields a high transmission of up to 66.4% at 530 nm and a power conversion efficiency (PCE) of 2.11%. Moreover, the DTDCTB:C70 device demonstrates an exceptional PCE as high as 3.24% with a balanced transmission of ≈50% in the visible spectrum. Enhanced PCE values of transparent solar cells are also revealed with the use of external reflectors. Efficiency enhancements of ≈15% and ≈65% are achieved by simply attaching a reflection mirror at the cathode or anode side, respectively.  相似文献   

3.
Three 2,2-dicyanovinyl (DCV) end-capped A-π-D-π-A type oligothiophenes (DCV-OTs) containing dithieno[3,2-b:2′,3′-d]silole (DTSi), cyclopenta[1,2-b:3,4-b′]dithiophene (DTCP) or dithieno[3,2-b:2′,3′-d]pyrrole (DTPy) unit as the central donor part, mono-thiophene as the π-conjugation bridge were synthesized. The absorption spectroscopies, cyclic voltammetry of these compounds were characterized. Results showed that all these compounds have intensive absorption band over 500–680 nm with a LUMO energy level around −3.80 eV, which is slightly higher than that of [6,6]phenyl-C61-butyric acid methyl ester (PC61BM, ELUMO = −4.01 eV), but lower than that of poly(3-hexylthiophene) (P3HT, ELUMO = −2.91 eV). Solution processed bulk heterojunction “all-thiophene” solar cells using P3HT as electron donor and the above mentioned oligothiophenes as electron acceptor were fabricated and tested. The highest power conversion efficiency (PCE) of 1.31% was achieved for DTSi-cored compound DTSi(THDCV)2, whereas PTB7:DTSi(THDCV)2 based device showed slightly higher PCE of 1.56%. Electron mobilities of these three compounds were measured to be around 10−5 cm2 V−1 s−1 by space charge limited current method, which is much lower than that of PC61BM, and was considered as one of the reason for the low photovoltaic performance.  相似文献   

4.
Sol–gel processible organosilicate material based on dialkylviologen (1,1-(bis-trimethoxysilane)-[4,4′]bipyridium dibromide (bis-trimethoxypropylsilane)-yl-viologen, PV-Si) was synthesized and used as an interfacial layer material for polymer solar cells based on poly(3-hexylthiophene): [6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM). PV-Si is very good soluble in polar protic solvents because of two pyrinium bromide salts and PV-Si pre-polymer can be easily prepared by sol–gel chemistry under the mild acidic conditions. From the ultraviolet spectroscopy (UPS) study, the reduction of the work function of Al and ITO is observed by the formation of interface dipole, which is induced by the thin film of thermally cured PV-Si pre-polymer (cPV-Si) at 180 °C. The open circuit voltage (Voc) of conventional type polymer solar cell (CPSC) with a structure of ITO/active layer (P3HT:PCBM)/cPV-Si(<5 nm)/Al is 0.58 V, which is higher than the CPSC without cPV-Si (0.55 V). This indicates that the favorable interface dipole is generated by the thin film of cPV-Si. Besides, the power conversion efficiency (PCE) of CPSC with cPV-Si reaches at 2.90%, which is higher than that of the device without cPV-Si (2.69%). Surprisingly, the PCE and the short circuit current (Jsc) of inverted type polymer solar cell (IPSC) with a structure of ITO/cPV-Si (<5 nm)/active layer/WO3/Ag are 2.83% and ?9.19 mA/cm2, respectively, which are higher than those of the device with ZnO (2.51% and ?8.63 mA/cm2) as an electron transporting/injecting layer. This is due to that the work function of ITO is also reduced by the formation of interface dipole. The IPSC with cPV-Si as an interfacial layer (IFL) shows very good rectification and a contact property as well. From the results, the thin layer of cPV-Si is potential material for an IFL for either CPSC or IPSC. Especially, ZnO can be replaced by cPV-Si because of their improved device performances and pretty low processing temperature.  相似文献   

5.
A heteroleptic polypyridyl ruthenium complex ‘cis-Ru(4,4′-bis(3,5-bis(5-hexylthiophen-2-yl)phenyl)-2,2′-bipyridine)(4,4′-dicarboxyl-2,2′-bipyridine) (NCS)2, MC102′, with a high molar extinction coefficient was synthesized and characterized with IR, 1H NMR, Mass, UV–Vis spectroscopy. The test cell DSSC devices constructed with 0.23 cm2 active area photo-electrode in combination with an electrolyte composed of 0.6 M dimethylpropyl-imidazolium iodide (DMPII), 0.05 M I2, and 0.1 M LiI in acetonitrile yielded solar to electric energy conversion efficiency (η) of 4.42% under Air Mass (AM) 1.5 sunlight, while the reference N719 sensitized solar cell fabricated and evaluated under similar conditions exhibited η-value of 5.84%.  相似文献   

6.
Three new metal-free organic dyes FD13 with a planar dithieno[3,2-b:2′,3′-d]pyrrole unit as linker were synthesized and used for dye-sensitized solar cells with high molar extinction coefficients. In this work, dithieno[3,2-b:2′,3′-d]pyrrole was employed as π-conjugated bridge to construct A–π–d–π–A organic dyes, where 9,9-dihexyl-9H-fluorene was used as a donor, and cyanoacrylic acid as an electron acceptor. For a typical device, a solar energy conversion efficiency (η) of 6.36% based on FD2 was achieved under simulated AM 1.5 solar irradiation (100 mW cm?2) with a short-circuit photocurrent density (Jsc) of 13.76 mA cm?2, an open-circuit voltage (Voc) of 669 mV, a fill factor (ff) of 0.691. The results suggest that the organic dye with a functionalized dithienopyrrole unit is a promising candidate for DSSCs due to its high molar extinction coefficients.  相似文献   

7.
A solution processable A-D-A-D-A structure small molecule DCAEH5TBT using a BT unit as the core has been designed and synthesized for application in BHJ solar cells. The device employing DCAEH5TBT/PC61BM as active layer shows PCE of 2.43% without any post treatment. After thermal annealing (150 °C, 10 min), the PCE of this molecule based device increased to 3.07%, with Jsc of 7.10 mA/cm2, Voc of 0.78 V and FF of 55.4%, which indicates that high performance of solution processed small molecule based solar cells can be achieved using thermal annealing by carefully design molecule structure.  相似文献   

8.
《Organic Electronics》2014,15(7):1324-1337
A tertiary arylamine compound (DC), which contains a terminal cyano-acetic group in one of its aryl groups, and an unsymmetrical porphyrin dyad of the type Zn[Porph]-L-H2[Porph] (ZnP-H2P), where Zn[Porph] and H2[Porph] are metallated and free-base porphyrin units, respectively, and L is a bridging triazine group functionalized with a glycine moiety, and were synthesized and used for the fabrication of co-sensitized dye-sensitized solar cells (DSSCs). The photophysical and electronic properties of the two compounds revealed spectral absorption features and frontier orbital energy levels that are appropriate for use in DSSCs. Following a stepwise co-sensitization procedure, by immersing the TiO2 electrode in separate solutions of the dyes in different sequence, two co-sensitized solar cells were obtained: devices C (ZnP-H2P/DC) and D (DC/ZnP-H2P).The two solar cells were found to exhibit power conversion efficiencies (PCEs) of 6.16% and 4.80%, respectively. The higher PCE value of device C, which is also higher than that of the individually sensitized devices based on the ZnP-H2P and DC dyes, is attributed to enhanced photovoltaic parameters, i.e. short circuit current (Jsc = 11.72 mA/cm2), open circuit voltage (Voc = 0.72 V), fill factor (FF = 0.73), as it is revealed by photovoltaic measurements (JV curves) and by incident photon to current conversion efficiency (IPCE) spectra of the devices, and to a higher total dye loading. The overall performance of device C was further improved up to 7.68% (with Jsc = 13.45 mA/cm2, Voc = 0.76 V, and FF = 0.75), when a formic acid treated TiO2 ZnP-H2P co-sensitized photoanode was employed (device E). The increased PCE value of device E has been attributed to an enhanced Jsc value (=13.45 mA/cm2), which resulted from an increased dye loading, and an enhanced Voc value (=0.76 V), attributed to an upward shift and increased of electron density in the TiO2 CB. Furthermore, dark current and electrochemical impedance spectra (EIS) of device E revealed an enhanced electron transport rate in the formic acid treated TiO2 photoanode, suppressed electron recombination at the photoanode/dye/electrolyte interface, as well as shorter electron transport time (τd), and longer electron lifetime (τe).  相似文献   

9.
Four new host/hole-transporting materials, namely 4,4′,4″,4‴-(adamantane-1,3,5,7-tetrayl)tetrakis(N,N-diphenylaniline) (4TPA-Ad, 1),4,4′,4″,4‴-(adamantane-1,3,5,7-tetrayl)tetrakis(N,N-di-p-tolylaniline) (4MTPA-Ad, 2), 1,3,5,7-tetrakis(4-(9H-carbazol-9-yl)phenyl)adamantane (4Cz-Ad, 3) and 1,3,5,7-tetrakis(4-(3,6-di-tert-butyl-9H-carbazol-9-yl)phenyl)adamantane (4tBuCz-Ad, 4), were designed and synthesized by incorporating four electron-donating arylamine units into the rigid adamantane skeleton via a simple C–N coupling reaction. Their thermal, photophysical and electrochemical properties were investigated. The molecular design endows the materials with high triplet energies of ∼3.0 eV, good solution processability, high thermal stability and appropriate HOMO levels. Two types of electroluminescent devices using 14 as hole-transporting or host materials were fabricated. The device based on 2 as solution-processed hole-transporting material and tris(quinolin-8-yloxy)aluminum as an emitter revealed a maximum current efficiency of 4.2 cd A−1, which was comparable with the TAPC-based control device. The sky-blue device employing 2 as solution-processed host material and 4,6-(difluorophenyl)pyridine-N,C2′)picolinate (FIrpic) as an emitter showed a maximum current efficiency of 16.6 cd A−1 with Commission Internationale de I’Eclairage (CIE) coordinates of (0.16, 0.32).  相似文献   

10.
A new donor–acceptor (D?A) copolymer (PIPY–DTBTA) containing 6,12-dihydro-diindeno[1,2-b;1′,2′-e]pyrazine donor and benzotriazole acceptor was synthesized and characterized for multifunctional applications in organic field-effect transistors (OFETs), polymer solar cells (PSCs) and polymer light-emitting diodes (PLEDs). The polymer exhibits high molecular weights, excellent film-forming ability, a deep HOMO energy level, and good solution processability. Solution-processed thin film OFETs based on this polymer revealed good p-type characteristic with a high hole mobility up to 0.0521 cm2 V?1 s?1. Bulk-heterojunction PSCs comprising this polymer and PC61BM gave a power conversion efficiency (PCE) of 0.77%. The single-layer PLEDs based on PIPY–DTBTA emitted a yellow–red light with a maximum brightness of 385 cd m?2 at the turn-on voltage of 6 V.  相似文献   

11.
《Organic Electronics》2014,15(8):1780-1790
We report the photophysical, electrochemical and theoretical properties of two dyes with same acceptor, π-linker and anchoring acceptor unit and different TPA (D1) and pyran (D2) donor central unit. The change in the central unit resulted in corresponding different photophysical and electrochemical properties. The dye sensitized solar cell fabricated using dye D1 showed the higher incident photon to current efficiency of 54%, a short circuit current (Jsc) of 11.86 mA/cm2, an open circuit voltage of 0.64 V, and fill factor (FF) of 0.68, corresponding an overall power conversion efficiency of 5.16% which is higher than that for D2 based DSSCs (4.42%). The difference in the PCE of DSSCs based on D1 and D2 is partly, due to the smaller amount of dye loading, higher dark current and charge recombination rate of D1 based DSSC. The electrochemical spectra of DSSCs demonstrated longer electron life time and charge recombination resistance and small charge transport resistance for D1 sensitized DSSC, results the higher PCE.  相似文献   

12.
This paper reports polymer solar cells with a 7% power conversion efficiency (PCE) based on bulk heterojunction (BHJ) composites of the alternating co-polymer, poly[N-9′′-hepta-decanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole) (PCDTBT), and the fullerene derivative [6,6]-phenyl C71-butyric acid methyl ester (PC71BM). As confirmed by transmission electron microscopy, solvent–vapor annealing (SVA) of the thin (70 nm) BHJ photoactive layer by exposure to chloroform vapor, for a short period of time (30 s) after deposition, leads to reconstructed nanoscale morphology of donor/acceptor domains, well-dispersed fullerene phase and effective photo-absorption of BHJ. Consequently, SVA-reconstructed devices with a PCDTBT:PC71BM blend ratio of 1:5 (wt%) exhibit ~50% improvement in PCE, with short-circuit current Jsc = 15.65 mA/cm2, open-circuit voltage Voc = 0.87 V, and PCE = 7.03%, in comparison to those of the 1:4 (wt%) blends with SVA treatment.  相似文献   

13.
Inverted pyramids were fabricated through a method combining cesium chloride (CsCl) self-assembly technology and anisotropy corrosion of silicon solar cells. Ti film with nanoporous masks was formed by lift-off the CsCl nanoislands for the inverted pyramids. The pyramids were then formed by anisotropy corrosion of alkaline solution. The average diameter and morphology of the pyramids were controlled by varying the average diameter of CsCl nanoislands from 400 nm to 1.5 µm and by varying the etching time of alkaline solution from 2 to 8 min. The inverted-pyramid texture could suppress reflection to below 10% at wavelengths from 400 to 1000 nm, which was much lower than that of planar wafer. A solar cell fabricated from the pyramids had higher short-circuit current density (Jsc) and photovoltaic conversion efficiency (PCE) compared with those of planar solar cells for the good antireflection property. The solar cell showed a PCE of 15.25%, a Jsc of 38.35 mA/cm2, and an open-circuit voltage of 555.7 mV.  相似文献   

14.
New large-bandgap host materials with carbazole and carboline moieties were designed and synthesized for high-performance blue phosphorescent organic light-emitting diodes (PhOLEDs). The two kinds of host materials, 9-(4-(9H-carbazol-9-yl)phenyl)-6-(9H-carbazol-9-yl)-9H-pyrido[2,3-b]indole (pP2CZCB) and 9-(3-(9H-carbazol-9-yl)phenyl)-6-(9H-carbazol-9-yl)-9H-pyrido[2,3-b]indole (mP2CZCB), displayed promisingly high triplet energies of ∼2.92–2.93 eV for enhancing the exothermic energy transfer to bis[2-(4,6-difluorophenyl)pyridinato-C2,N](picolinato)iridium(III) (FIrpic) in PhOLED devices. It was found that the blue PhOLEDs bearing the new host materials and the FIrpic dopant exhibited markedly higher external quantum efficiencies (EQEs) than a device made with 1,3-bis(N-carbazolyl)benzene (mCP) as the host. In particular, the PhOLED device made with 3 wt% FIrpic as the dopant and mP2CZCB as the host material displayed a low driving voltage of 4.13 V and the high EQE of 25.3% at 1000 cd m−2.  相似文献   

15.
Two new conjugated D–A polymers P3 (PBTT-d-BTT) and P4 (PBTT-d-TPD) based on same benzo[1,2-b:3,4-b′:6,5-b″] trithiophene (BTT) donor and different acceptors monomers 5,8-dibromo-2-dodecanoylbenzo[1,2-b:3,4-b′:6,5-b″] trithiophene (d-BTT), and 1,3-dibromo-5-(2-ethylhexyl)thieno[3,4]pyrrol-4,6-dione (d-TPD) respectively, were synthesized by Stille cross-coupling reaction and characterized by gel permeation chromatography (GPC), 1H NMR, UV–Vis absorption, thermal analysis and electrochemical cyclic voltammetry (CV) tests. Photovoltaic properties of the polymers were studied by using the polymers as donor and PC71BM as acceptor with a weight ratio of polymer:PC71BM 1:1, 1:2 and 1:2.5. The optimized photovoltaic device was fabricated with an active layer of a blend P3:PC71BM and P4:PC71BM with a blend ratio of 1:2 showed PCE 3.16% and 2.42%, respectively under illumination of AM 1.5 at 100 mW/cm2 with solar simulator. The PCE of the device based on P3:PC71BM processed with DIO/o-DCB has been further improved up to 4.64% with Jsc of 10.52 mA/cm2 and FF of 0.58 attributed to the increase in crystalline nature of active layer and more balanced charge transport in the device, induced by DIO additive.  相似文献   

16.
We synthesized solution-processable iridium complexes having bulky carbazole dendrons, fac-tris[2-{3-(3,5-bis(3,6-di-n-butylcarbazol-9-yl)phenyl)Phenyl)pyridine]iridium (III) (mCP)3Ir and fac-bis[2-{3-(3,5-bis(3,6-di-n-butylcarbazol-9-yl)phenyl)phenyl}pyridine][2-{3-(3,5-di(4-pyridyl)phenyl)phenyl}pyridine]iridium (III) (mCP)2(bpp)Ir. Photoluminescence quantum efficiencies (PLQEs) of (mCP)3Ir and (mCP)2(bpp)Ir in their diluted solutions were 91% and 84%, respectively. They showed high PLQEs of 49% for (mCP)3Ir and 29% for (mCP)2(bpp)Ir even in a neat film. The triplet exciton energy level of the dendronized ligand (2.8 eV), 2-[3-{3,5-bis(3,6-di-n-butylcarbazol-9-yl)phenyl}]pyridine 10, and the dendron (2.9 eV), 3,5-bis(3,6-di-n-butylcarbazol-9-yl)benzene 7, are enough higher than that of the core complex Ir(ppy)3 (2.6 eV). External quantum efficiency (EQE) of single layer light-emitting device with (mCP)2(bpp)Ir was much higher than that of (mCP)3Ir because of better affinity of (mCP)2(bpp)Ir to cathode metal. When an electron transporting and hole-blocking material was used, the EQEs of double layer devices were dramatically improved to 8.3% for (mCP)3Ir and 5.4% for (mCP)2(bpp)Ir at 100 cd/m2.  相似文献   

17.
We designed and synthesized a series of highly soluble random copolymers (P(BDTT-PhC8TPD-TPD)) comprising a two-dimensional (2D) electron-rich 2-ethylhexylthiophene-substituted benzo[1,2-b:4,5-b′]dithiophene (M1) electron-rich unit and various ratios of two side chain-functionalized thieno[3,4-c]-pyrrole-4,6-diones (M2 and M3) as planar electron-deficient units. The morphologies and photovoltaic performances of the bulk heterojunction blend films were examined, revealing concentration-dependent competitive benzene–benzene and benzene–fullerene interactions. A bulk heterojunction solar cell prepared using 10 mol% M2 (RP1) and PC70BM exhibited a power conversion efficiency (PCE) of 4.9%, representing a significant improvement over the PCE (1.1%) obtained from parent copolymer (P1). The PCE in these cells was strongly associated with the nanoscale morphology of the BHJ film, which depended on the higher miscibility of RP1 with PC70BM compared to RP2 (M2: 20 mol%), and RP3 (M2: 30 mol%).  相似文献   

18.
《Organic Electronics》2014,15(1):266-275
Three novel carbazole-based A-π-D-π-A-featured dyes (CSG1CSG3) have been designed, synthesized for applications in dye-sensitized solar cells and fully characterized with NMR, MS, IR, UV–vis and electrochemical measurements. These dyes share the same donor (N-hexylcarbazole) and acceptor/anchoring group (cyanoacrylic acid), but differs in conjugated linkers incorporated, such as benzene, furan or thiophene, to configure the novel A-π-D-π-A framework for effective electron flow. The power conversion efficiencies were observed to be sensitive to the π-bridging linker moiety. The photovoltaic experiments showed that dye with a benzene linker exhibited a higher open-circuit voltage (0.699 V) compared to thiophene and furan linker. Among all dyes, CSG2 containing a thiophene linker exhibited the maximum overall conversion efficiency of 3.8% (JSC = 8.90 mA cm−2, VOC = 584 mV, FF = 0.74) under standard global AM 1.5 G solar condition. Under similar fabrication conditions, champion dye N719 exhibited the maximum overall conversion efficiency of 6.4% (JSC = 14.74 mA cm2, VOC = 606 mV, FF = 0.716).  相似文献   

19.
《Organic Electronics》2014,15(3):818-823
A medium band gap D–A copolymer of indacenodithiophene (IDT) and fluorinated dithienylbenzotriazole (FBTA), PIDT-FBTA, was synthesized for the application as donor material in polymer solar cells (PSCs). PIDT-FBTA showed deeper highest occupied molecular orbital (HOMO) energy level due to the strong electron-withdrawing difluorine substitution on benzotriazole acceptor unit in the D–A copolymer. The PSCs based on PIDT-FBTA:PC70BM (1:3) exhibited a high Voc of 0.90 V and a power conversion efficiency (PCE) of 3.62% under the illumination of AM 1.5G, 100 mW cm−2. The device performance was further improved by methanol treatment with PCE increased to 4.90% and Voc increased to 0.92 V.  相似文献   

20.
《Organic Electronics》2014,15(6):1189-1196
The fabrication of small-molecule bulk-heterojunction solar cells utilizing a mixed donor material composed of two types of soluble phthalocyanine derivatives with different substituent length has been studied. The power conversion efficiency (PCE) and short-circuit current density (Jsc) of the solar cells fabricated using the mixed donor material with an optimized mixture ratio reached 3.8% and 9.2 mA/cm2, respectively, which were superior to those of organic solar cells utilizing each type of phthalocyanine derivative as a single donor material. The improvement of PCE and Jsc has been discussed from the viewpoints of the miscibility and carrier transport properties of the mixed donor material.  相似文献   

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