Gene

Quantum mechanics

Non-radiative recombination

Acceptor

Semiconductor materials

Engineering

Chemical physics

Materials science

Atomic physics

Biochemistry

Semiconductor

Radiative transfer

Laser

Physics

Exciton

Optics

Recombination

Molecular physics

Charge carrier

Condensed matter physics

Charge (physics)

Chemistry

Energy conversion efficiency

Organic solar cell

Optoelectronics

Photovoltaic system

Spontaneous emission

Electrical engineering

Engineering physics

Joule

<h2>Summary</h2> Reducing non-radiative charge recombination is of critical importance to achieving high-performance organic photovoltaic (OPV) cells. The correlation between the exciton behaviors and non-radiative charge recombination is rarely studied. In this work, we achieved an increase in the exciton diffusion length (LD) in the acceptor phase via introducing HDO-4Cl to the PBDB-TF:eC9-based system. Compared with the eC9-based film, the exciton LD in the HDO-4Cl:eC9-based film is increased from 12.2 to 16.3 nm. The enlarged exciton LD can obviously decrease the non-radiative charge recombination and increase the efficiency of photon utilization in the PBDB-TF:eC9-based OPV cell. Finally, we not only obtained an outstanding power conversion efficiency (PCE) of 18.86% but also demonstrated the correlations between the non-radiative energy loss and exciton behaviors. The results show that regulating the exciton behaviors is an effective way to reduce the non-radiative energy loss and realize high-efficiency OPV cells.

Reduced non-radiative charge recombination enables organic photovoltaic cell approaching 19% efficiency