Understanding the Nonradiative Charge Recombination in Organic Photovoltaics: From Molecule to Device

Advanced Functional Materials, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 19, 2024

Abstract Organic photovoltaics (OPVs) have made significant strides with efficiencies now exceeding 20%, positioning them as potential competitors to inorganic solar technologies. One of the most critical challenges toward this goal is severe open‐circuit voltage ( V oc ) loss caused by nonradiative charge recombination (NRCR). Herein, review comprehensively summarizes NRCR mechanisms and suppression techniques OPVs across various scales from molecule device. Specifically, origins in a single are first summarized, molecular design principles high photoluminescence quantum yield reviewed following Marcus theory. Next, effect aggregation on reviewed, well processing strategies modulate film packing for suppression. Furthermore, progresses avoidance pathways mediated transfer states triplet donor:acceptor bulk heterojunctions tracked. Besides, interfacial optimization device structure maximize electroluminescent efficiency presented. Finally, several curtailing high‐performance outlined. Therefore, shows an insightful perspective understand mitigate at multi‐scales, poised provide clear roadmap next breakthrough OPVs.

Language: Английский

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Low‐Volatility Fused‐Ring Solid Additive Engineering for Synergistically Elongating Exciton Lifetime and Mitigating Trap Density Toward Organic Solar Cells of 20.5% Efficiency

Advanced Materials, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 12, 2025

Abstract Volatile solid additives (VSAs) with single or fused‐ring structures have attracted much attention for enhancing power conversion efficiencies (PCEs) of organic solar cells (OSCs). While the working mechanisms high‐volatility single‐ring been well studied, influence low‐volatility VSAs on molecular aggregations and exciton/carrier dynamics remains still unclear. Herein, 3,6‐dibromothieno[3,2‐b]thiophene (3,6TTBr) is selected as a representative VSA to elucidate its mechanism. Via theoretical experimental joint investigation, it found that rigid planar 3,6TTBr molecules adsorb onto terminal units L8‐BO (acceptor), inducing loose space adjacent molecules. The thus favors center‐terminal packing larger interfragment distance, which relieves over‐aggregation induces ordered packing. Consequently, treatment reduces aggregation‐caused quenching, photoluminescence quantum yield exciton lifetime film. combination above properties reduced trap density improved carrier transport in 3,6TTBr‐treated devices contributed PCE 20.1%. To validate broad applicability findings, 1,5‐dibromonaphthalene (1,5‐BN), another solid, explored. 1,5‐BN achieved an impressive 20.5%, verifying validity strategy boosting OSC performances.

Language: Английский

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Improving the Photovoltaic Performance of PBDB-T:PC₇₁BM-Based Ternary Solar Cells by Employing Arylmethylene-Substituted Small Molecules as the Guest Acceptor

ACS Applied Energy Materials, Journal Year: 2024, Volume and Issue: 7(5), P. 1993 - 2007

Published: Feb. 19, 2024

Four arylmethylene-substituted small-molecule acceptors (SMAs), IDTV-SiIC, IDTVT-PhIC, m-IDTV-PhIC, and DTCFDV-IC were introduced to the host PBDB-T:PC71BM binary system as a guest acceptor construct PBDB-T:PC71BM:SMA ternary polymer solar cells (PSCs), respectively. After optimization, these PSCs exhibit power conversion efficiencies (PCEs) of 8.93%, 9.28%, 9.68%, 9.78% for DTCFDV-IC, respectively, all which are higher than those PSC regardless device structures (inverted or conventional devices). The improved PCE is first attributed increased open-circuit voltage (Voc) due upshifted lowest unoccupied molecular orbital level an alloy between (PC71BM) (SMAs). model verified by exploring relationship Voc feed ratio SMA in blend, cyclic voltammetry measurements, miscibility two kinds acceptors. Furthermore, fill factors also play key role improving PCEs, could be ascribed enhanced more balanced carrier mobilities, exciton dissociation, reduced charge recombination, optimized morphology active layers after such SMAs added acceptor. In particular, IDTV-SiIC-based thick-film devices prepared, results demonstrate that has better film thickness tolerance compared with device, suggesting great potential fabricating photovolatic devices. Additionally, relative PM6:L8-BO (17.18%), 18.20% was achieved PM6:L8-BO:DTCFDV-IC PSC, acceptor, implying have certain potentiality constructing high-efficiency PSCs. This work suggests incorporation third component feasible effective strategy obviously enhance efficiency.

Language: Английский

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Optimizing Exciton Diffusion and Carrier Transport for Enhanced Efficiency in Q‐PHJ and BHJ Organic Solar Cells

Advanced Functional Materials, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 5, 2024

Abstract Exciton diffusion and carrier transport are two critical factors that determine the efficiency of organic photovoltaics (OPVs). However, relationship between these has not been extensively studied. Designing non‐fullerene acceptors (NFAs) with efficient coefficients high electronic transmittance is a key area focus. In this study, materials for bulk‐heterojunction (BHJ) quasiplanar‐heterojunction (Q‐PHJ) devices synthesized to validate desired differences in crystallinity. The single crystal BOBO4Cl‐ βδ demonstrated most compact packing structure, an improved planar configuration closer π···π distances, resulting higher electron mobility superior exciton coefficient. Consequently, ‐based achieved power conversion (PCE) 17.38% Q‐PHJ, compared lower PCE 14.75% BHJ devices. Furthermore, incorporating into D18/L8‐BO Q‐PHJ system increased from 17.98% 18.81%, one highest values recorded This improvement attributed strong crystallinity , which enhances arrangement improves Our work highlights importance molecular design tunable OPV architectures reveals them, contributes achievement high‐performance NFAs.

Language: Английский

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Towards efficient and stable organic solar cells: fixing the morphology problem in block copolymer active layers with synergistic strategies supported by interpretable machine learning

Energy & Environmental Science, Journal Year: 2024, Volume and Issue: 17(22), P. 8954 - 8965

Published: Jan. 1, 2024

Interpretable machine learning identifies the causal structure–property relationships and key control factors in block copolymer organic solar cells with excellent power conversion efficiency thermal stability.

Language: Английский

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