Reducing energy loss via tuning energy levels of polymer acceptors for efficient all-polymer solar cells
Artikel i vetenskaplig tidskrift, 2020

The open-circuit voltage (Voc) of all-polymer solar cells (all-PSCs) is typically lower than 0.9 V even for the most efficient ones. Large energy loss is the main reason for limiting Voc and efficiency of all-PSCs. Herein, through materials design using electron deficient building blocks based on bithiophene imides, the lowest unoccupied molecular orbital (LUMO) energy levels of polymer acceptors can be effectively tuned, which resulted in a reduced energy loss induced by charge generation and recombination loss due to the suppressed charge-transfer (CT) state absorption. Despite a negligible driving force, all-PSC based on the polymer donor and acceptor combination with well-aligned energy levels exhibited efficient charge transfer and achieved an external quantum efficiency over 10% while maintaining a large Voc of 1.02 V, leading to a 9.21% efficiency. Through various spectroscopy approaches, this work sheds light on the mechanism of energy loss in all-PSCs, which paves an avenue to achieving efficient all-PSCs with large Voc and drives the further development of all-PSCs.

all-polymer solar cells

energy level modulation

photovoltage

polymer acceptors

energy loss

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Publicerad i

Science China Chemistry

1674-7291 (ISSN) 18691870 (eISSN)

Vol. 63 Nummer/häfte 12 s. 1785-1792

Kategorisering

Ämneskategorier (SSIF 2011)

Annan fysik

Energisystem

Den kondenserade materiens fysik

Identifikatorer

DOI

10.1007/s11426-020-9826-4

Mer information

Senast uppdaterat

2020-12-03