Theory‐Guided Material Design Enabling High‐Performance Multifunctional Semitransparent Organic Photovoltaics without Optical Modulations

Abstract

Semitransparent organic photovoltaics (ST‐OPVs) have drawn great attention for promising applications in building‐integrated photovoltaics, providing additional power generation for daily use. A previously proposed strategy, “complementary NIR absorption,” is widely applied for high‐performance ST‐OPVs. However, rational material design toward high performance has not been achieved. In this work, an external quantum efficiency (EQE) model describing this strategy is developed to explore the full potential of material design on ST‐OPV performance. Guided by the model, a novel nonfullerene acceptor (NFA), ATT‐9, is designed and synthesized, which possesses optimal bandgap for ST‐OPVs, achieving a record short‐circuit current density of 30 mA cm−2 and a power conversion efficiency of 13.40%, the highest value among devices based on NFAs with bandgaps lower than 1.2 eV. It is notworthy that, at such a low bandgap, the energy loss of the device is only 0.58 eV, which is attributed to the low energetic disorder confirmed by an ultralow Urbach energy of 21.6 meV. Benefiting from the optimal bandgap and low energy loss, the ATT‐9‐based ST‐OPV achieves a high light utilization efficiency of 3.33% without optical modulations, and meanwhile shows excellent thermal insulation, exceeding the commercial 3M heat‐insulating window film, demonstrating the outstanding application prospects of multifunctional ST‐OPVs.

Efficient Optoelectronic Devices Enabled by Near-Infrared Organic Semiconductors with a Photoresponse beyond 1050 nm

“…Meanwhile, the ST-OSC device achieves a decent PCE of 6.15%, accompanied by an average visible transmittance (AVT) of 38.79%. Notably, Zhu et al reported a similar molecule ATT-9 exhibiting a PCE of 9.37% and an AVT of 35.5% while we were preparing this paper . Furthermore, the OPD device based on PTB7-Th:BFIC delivers an impressive specific detectivity of over 10 13 Jones in a broad spectrum ranging from 330 to 1030 nm …”

“…The relatively high charge mobility is conducive to reducing space charge accumulation and thus facilitating efficient charge extraction, consequently leading to the high FF of the relevant OSC . Eventually, the BFIC-based device achieves over 10% PCE, which is one of only a few examples of OSCs fabricated by ultranarrow band-gap organic semiconductors. ,,,, …”

“…Notably, Zhu et al reported a similar molecule ATT-9 exhibiting a PCE of 9.37% and an AVT of 35.5% while we were preparing this paper. 32 Furthermore, the OPD device based on PTB7-Th:BFIC delivers an impressive specific detectivity of over 10 13 Jones in a broad spectrum ranging from 330 to 1030 nm. 33 ■ RESULTS AND DISCUSSION Synthesis and Characterization.…”

Rationally regulating the π-bridge of small molecule acceptors for efficient organic solar cells

“…For example, alkylthio thiophene π-bridged ACS8 (ITIC derivative) and thieno[3,4- b ]thiophene π-bridged ATT-9 (Y6 derivative) have recorded an impressive J SC of up to 25.3 and 30.0 mA cm −2 , respectively. 15,16 However, the consequent high-level highest occupied molecular orbital (HOMO) and low-lying lowest unoccupied molecular orbital (LUMO) levels not only limit the utilization of donor materials, but also reduce the open-circuit voltages ( V OC ) of the resultant OSCs. Another outcome that should be particularly noted is that the π-bridge segment could give rise to two opposite impacts on intermolecular stacking, that is, the unfavorable irregularity induced by rotatable σ-bonds and favorable extension of π-conjugated planes.…”

High-Efficiency Ternary Organic Solar Cells with a Good Figure-of-Merit Enabled by Two Low-Cost Donor Polymers

“…Promising developments have been made in organic solar cells (OSCs) in recent years, with the power conversion efficiency (PCE) of the best devices exceeding 18%. − The high PCE of this photovoltaic (PV) technology, together with other benefits such as flexibility, color tunability, and easy fabrication, contributes to its market competitiveness. − On the other hand, the scalability and cost management of material synthesis and device production are the next issues to solve in order achieve wide-scale commercialization. To evaluate the cost components related to chemical synthesis, researchers in the field have proposed several concepts, such as synthetic complexity (SC), scalability factor (SF), and figure of merit (FoM). − …”