Long-lived and disorder-free charge transfer states enable endothermic charge separation in efficient non-fullerene organic solar cells.
Long-lived and disorder-free charge transfer states enable endothermic charge separation in efficient non-fullerene organic solar cells.
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DOI：
10.1038/s41467-020-19332-5
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发表时间：
2020-11-05
影响因子：
16.6
通讯作者：
Chow PCY
中科院分区：
文献类型：
--
作者：
Hinrichsen TF;Chan CCS;Ma C;Paleček D;Gillett A;Chen S;Zou X;Zhang G;Yip HL;Wong KS;Friend RH;Yan H;Rao A;Chow PCY
基于非富勒烯受体的有机太阳能电池可以在接近零的施主-受主能量偏置的情况下表现出高的电荷产生率，以驱动电荷分离，并克服电子和空穴之间的库仑相互吸引。在这里，我们使用时间分辨光学光谱来表明，这些体系中的自由电荷是由界面电荷转移态的热激活解离产生的，这种离解在室温下发生在数百皮秒内，比基于富勒烯的同类体系慢三个数量级。在后来的自由电子-空穴相遇时，电荷转移态和发射激子都被再生，从而在激子、电荷转移态和自由电荷之间建立了平衡。我们的结果表明，在这些体系中形成长寿命和无序的电荷转移态使它们能够在接近准热力学的条件下工作，而不需要能量补偿来驱动界面电荷分离和实现抑制的非辐射复合。设计高效的有机太阳能电池受到克服电子和空穴之间的库仑相互吸引所需能量的限制。在这里，作者揭示了在具有边际能量补偿的非富勒烯系统中，长寿命和无无序的电荷转移态能够实现有效的吸热电荷分离。
Organic solar cells based on non-fullerene acceptors can show high charge generation yields despite near-zero donor–acceptor energy offsets to drive charge separation and overcome the mutual Coulomb attraction between electron and hole. Here, we use time-resolved optical spectroscopy to show that free charges in these systems are generated by thermally activated dissociation of interfacial charge-transfer states that occurs over hundreds of picoseconds at room temperature, three orders of magnitude slower than comparable fullerene-based systems. Upon free electron–hole encounters at later times, both charge-transfer states and emissive excitons are regenerated, thus setting up an equilibrium between excitons, charge-transfer states and free charges. Our results suggest that the formation of long-lived and disorder-free charge-transfer states in these systems enables them to operate closely to quasi-thermodynamic conditions with no requirement for energy offsets to drive interfacial charge separation and achieve suppressed non-radiative recombination. Designing efficient organic solar cells is limited by the energy required to overcome the mutual Coulomb attraction between electron and hole. Here, the authors reveal long-lived and disorder-free charge-transfer states enable efficient endothermic charge separation in non-fullerene systems with marginal energy offset.
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影响因子：
16.6
作者：
Causa, Martina;De Jonghe-Risse, Jelissa;Scarongella, Mariateresa;Brauer, Jan C.;Buchaca-Domingo, Ester;Moser, Jacques-E.;Stingelin, Natalie;Banerji, Natalie
通讯作者：
Banerji, Natalie
影响因子：
56.7
作者：
Classen, Andrej;Chochos, Christos L.;Brabec, Christoph J.
通讯作者：
Brabec, Christoph J.
影响因子：
15
作者：
Dimitrov, Stoichko D.;Bakulin, Artem A.;Durrant, James R.
通讯作者：
Durrant, James R.
影响因子：
27.8
作者：
Nikolis, Vasileios C.;Benduhn, Johannes;Vandewal, Koen
通讯作者：
Vandewal, Koen
影响因子：
29.4
作者：
Chen, Shangshang;Wang, Yuming;Yan, He
通讯作者：
Yan, He