04 Jul 03:18
by Di Wang,
Ran Qin,
Guanqing Zhou,
Xue Li,
Ruoxi Xia,
Yuhao Li,
Lingling Zhan,
Haiming Zhu,
Xinhui Lu,
Hin‐Lap Yip,
Hongzheng Chen,
Chang‐Zhi Li
High‐performance semitransparent organic solar cells are achieved through the combined design efforts on the formulation of near‐infrared ternary blends and optical control over photonic reflectors, which exhibit excellent features of power generation, they being see‐through, and infrared reflection.
Abstract
Clean energy production and saving play vital impacts on the sustainability of the global community. Herein, high‐performance semitransparent organic solar cells (ST‐OSCs) with excellent features of power generation, being see‐through, and infrared reflection of heat dissipation, with promising perspectives for building‐integrated photovoltaics (BIPVs) are reported. To simultaneously improve average visible transmittance (AVT) and power conversion efficiency (PCE), formally in a trade‐off relationship, of ST‐OSCs, new ternary blends with alloy‐like near‐infrared (NIR) acceptors are employed, which are effective to improve device efficiency while maintaining visible absorption unchanged, resulting in PCEs of 16.8% for opaque devices and 13.1% for semitransparent OSCs (AVT of 22.4% and infrared photon radiation rejection (IRR) of 77%). Further, multifunctional ST‐OSCs are realized via introducing simple, yet effective photonic reflectors, together with optical simulation, leading to not only perfect fitting of the visible transmittance peak (555 nm) to the photopic response of the human eye but also an excellent IRR of 90% (780–2500 nm), along with 23% AVT and over 12% PCE. This is thought to be the best‐performing multifunctional ST‐OSC with promising prospects as BIPVs in terms of power generation, heat dissipation, and being see‐through.
06 Mar 09:02
by Long Ye, Wenchao Zhao, Sunsun Li, Subhrangsu Mukherjee, Joshua H. Carpenter, Omar Awartani, Xuechen Jiao, Jianhui Hou, Harald Ade
Organic solar cells (OSCs) made of donor/acceptor bulk-heterojunction active layers have been of widespread interest in converting sunlight to electricity. Characterizing of the complex morphology at multiple length scales of polymer:nonfullerene small molecular acceptor (SMA) systems remains largely unexplored. Through detailed characterizations (hard/soft X-ray scattering) of the record-efficiency polymer:SMA system with a close analog, quantitative morphological parameters are related to the device performance parameters and fundamental morphology–performance relationships that explain why additive use and thermal annealing are needed for optimized performance are established. A linear correlation between the average purity variations at small length scale (≈10 nm) and photovoltaic device characteristics across all processing protocols is observed in ≈12%-efficiency polymer:SMA systems. In addition, molecular interactions as reflected by the estimated Flory–Huggins interaction parameters are used to provide context of the room temperature morphology results. Comparison with results from annealed devices suggests that the two SMA systems compared show upper and lower critical solution temperature behavior, respectively. The in-depth understanding of the complex multilength scale nonfullerene OSC morphology may guide the device optimization and new materials development and indicates that thermodynamic properties of materials systems should be studied in more detail to aid in designing optimized protocols efficiently.
Quantitative morphological parameters correlate well with the photovoltaic performance of six high-efficiency nonfullerene small molecular acceptors systems. Synergistic higher π–π coherence lengths and average domain purity result in over 12% efficiency fullerene-free organic solar cell (OSC) with a sequential treatment of solvent additive and thermal annealing. The work highlights the need for more detailed studies into the thermodynamics of OSCs.
