Low nonradiative energy losses within 0.2 eV in efficient non-fullerene all-small-molecule organic solar cells

Huang, Ziyun; Shi, Yanan; Chang, Yilin; Yang, Chen; Lv, Min; Shen, Yifan; Liu, Yanan; Zhang, Jianqi; Lü, Kun; Wei, Zhixiang

doi:10.1039/d1tc04264e

Cited by 11 publications

(11 citation statements)

References 55 publications

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“…Table 2 lists the corresponding PV parameters. The OPV incorporating the PM7:NTCPDTCN blend displayed the best performance, with a PCE of 3.65 ± 0.30%, a short-circuit current density (J SC ) of 7.72 ± 0.25 mA/ cm 2 , an open-circuit voltage (V OC ) of 1.04 ± 0.02 V, and a fill factor (FF) of 45.08 ± 4.04%. We attribute this high value of V OC to NTCPDTCN having the highest LUMO energy level among the three NFAs.…”

Section: Optical Absorption and Electrochemical Propertiesmentioning

confidence: 99%

“…OPVs appear likely to complement or replace traditional solar cells in applications such as power source for greenhouse lighting, indoor light harvesting, floating photovoltaics (PVs), and self-powered wearable sensors/smart clothing. − Very recently, great strides have been made in overcoming the low power conversion efficiencies (PCEs) and instabilities, further promoting this technology toward practical commercialization. Several publications have demonstrated single-junction OPVs displaying breakthrough PCEs (> 18%) − and superior long-term stability when exposed to light, heat, or air (without encapsulation). ,− These advances in the performance characteristics of OPVs can be attributed to the successful development of non-fullerene acceptors (NFAs), which possess highly tunable chemical structures ranging from small molecules to oligomers and polymers as well as outstanding optoelectronic properties. − …”

Section: Introductionmentioning

confidence: 99%

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High-Performance Ternary Organic Photovoltaics Incorporating Small-Molecule Acceptors with an Unfused-Ring Core

Jiang

You

Lin

et al. 2022

ACS Appl. Energy Mater.

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Organic photovoltaics (OPVs) have made enormous progress in recent years, benefiting from the rapid development of non-fullerene acceptors (NFAs). Most high-performance NFAs, however, have featured π-conjugated backbones with large-fused core structures, increasing the complexity and cost of their synthesis and limiting their practical commercialization. In this study, we synthesized a series of acceptor–donor–acceptor-configured small-molecule acceptors (NTCPDTCN, NTCPDTID, and NTCPDT2F) based on a core structure featuring a naphthobisthiadiazole (NT) group and two cyclopenta[2,1-b,3,4-b′]dithiophene (CPDT) groups as the unfused-ring central unit and equipping malononitrile (CN), 2-(3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (ID), and 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (2F) groups as terminal groups. When blended with PM7, the NTCPDTCN-containing binary device displayed a high open-circuit voltage (V OC) of 1.04 V, without self-aggregation, as well as the best device performance. When blended with PM6:Y6, the ternary NTCPDTCN-, NTCPDTID-, and NTCPDT2F-based OPVs provided power conversion efficiencies of 15.4 ± 0.09, 14.6 ± 0.15, and 16.0 ± 0.08%, respectively. NTCPDT2F provided complementary absorption and allowed fine-tuning of the blend morphology, resulting in suppression of charge recombination and improvements in charge generation and collection, thereby achieving the highest device performance. Thus, our findings might provide some directions for developing high-performance ternary OPVs through the introduction of unfused-ring small-molecule acceptors.

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Section: Optical Absorption and Electrochemical Propertiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

High-Performance Ternary Organic Photovoltaics Incorporating Small-Molecule Acceptors with an Unfused-Ring Core

Jiang

You

Lin

et al. 2022

ACS Appl. Energy Mater.

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“…[26][27][28][29][30][31] A lot of research has been devoted to developing all-small-molecule OSCs, and PCEs in the range of 15-17% have been attained for binary and ternary devices. [32][33][34][35][36][37][38] Herein, we have used two FFAs, i.e., one narrow bandgap and the other medium bandgap, denoted as F13 39 and IDT-IC, 40 respectively, and a wide bandgap small molecule C1-CN donor 41 for the construction of ternary ASM-OSCs. The chemical structures of these molecules are shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

“…26–31 A lot of research has been devoted to developing all-small-molecule OSCs, and PCEs in the range of 15–17% have been attained for binary and ternary devices. 32–38…”

Section: Introductionmentioning

confidence: 99%

All-small-molecule efficient ternary organic solar cells employing a coumarin donor and two fullerene-free acceptors

et al. 2023

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“…In order to further improve the performance of BHJ OSCs, it is imperative to reduce the energy loss ( E loss ) and increase V OC . [ 10–14 ]…”

Section: Introductionmentioning

confidence: 99%

Halogen‐Free Donor Polymers Based on Dicyanobenzotriazole with Low Energy Loss and High Efficiency in Organic Solar Cells

Wang

Zhang

Kim

et al. 2023

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With rapid advance of semiconductor materials, the highest power conversion efficiencies (PCE) of BHJ OSCs have been over 18%. [6][7][8][9] However, low open-circuit voltage (V OC ) and PCE of BHJ OSCs remain a significant challenge. In order to further improve the performance of BHJ OSCs, it is imperative to reduce the energy loss (E loss ) and increase V OC . [10][11][12][13][14] The E loss consists of radiative loss above bandgap (ΔE 1 ), radiative loss below bandgap (ΔE 2 ), and non-radiative recombination (ΔE 3 ). The value of ΔE 1 depends on the bandgaps of active layer materials, varying between 0.25 and 0.30 eV. [15] The ΔE 2 can be as low as 0.05 eV in OSCs, due to their effective charge separation. [16] The ΔE 3 is typically much larger than 0.1 eV in OSCs, [17][18][19] while ΔE 3 can be less than 0.1 eV in crystalline silicon solar cells. Hence, it is crucial to suppress non-radiative recombination (ΔE 3 ) of BHJ OSCs to reduce the E loss . [20][21][22][23][24][25] The ΔE 3 can be calculated from the equation: ΔE 3 = -kTln(EQE EL ) (where k is Boltzmann's constant, T is the absolute temperature, and EQE EL is external quantum efficiency of electroluminescence). Increasing the EQE EL can effectively reduce the non-radiativeHalogenation of organic semiconductors is an efficient strategy for improving the performance of organic solar cells (OSCs), while the introduction of halogens usually involves complex synthetic process and serious environment pollution problems. Herein, three halogen-free ternary copolymer donors (PCNx, x = 3, 4, 5) based on electron-withdrawing dicyanobenzotriazole are reported. When blended with the Y6, PCN3 with strong interchain interactions results in appropriate crystallinity and thermodynamic miscibility of the blend film. Grazing-incidence wide-angle X-ray scattering measurements indicate that PCN3 has more ordered arrangement and stronger π-π stacking than previous PCN2. Fourier-transform photocurrent spectroscopy and external quantum efficiency of electroluminescence measurements show that PCN3-based OSCs have lower energy loss than PCN2, which leads to their higher open-circuit voltage (0.873 V). The device based on PCN3 reaches power conversion efficiency (PCE) of 15.33% in binary OSCs, one of the highest values for OSCs with halogen-free donor polymers. The PCE of 17.80% and 18.10% are obtained in PM6:PCN3:Y6 and PM6:PCN3:BTP-eC9 ternary devices, much higher than those of PM6:Y6 (16.31%) and PM6:BTP-eC9 (17.33%) devices. Additionally, this ternary OSCs exhibit superior stability compared to binary host system. This work gives a promising path for halogen-free donor polymers to achieve low energy loss and high PCE.

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Low nonradiative energy losses within 0.2 eV in efficient non-fullerene all-small-molecule organic solar cells

Abstract: All-small-molecule organic solar cells with high photovoltaic performance and low non-radiative energy losses ≤ 0.2 eV.

Cited by 11 publications

References 55 publications

High-Performance Ternary Organic Photovoltaics Incorporating Small-Molecule Acceptors with an Unfused-Ring Core

High-Performance Ternary Organic Photovoltaics Incorporating Small-Molecule Acceptors with an Unfused-Ring Core

All-small-molecule efficient ternary organic solar cells employing a coumarin donor and two fullerene-free acceptors

Halogen‐Free Donor Polymers Based on Dicyanobenzotriazole with Low Energy Loss and High Efficiency in Organic Solar Cells

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