Organic solar cells (OSCs) offer significant advantages over traditional silicon devices, because of their lower costs, easier processability, improved mechanical properties, and chemically-tuneable electronic properties.1 The identification of novel donors and acceptors boosted up the power conversion efficiency (PCE) up to 19% for bulk heterojunction (BHJ) OSC;2 however, this value is still lower than their inorganic counterparts, thus hindering their commercialization. Theoretical studies have the potential to play a key role in the quest for higher PCE, by unravelling structure-property relations which can lead to the identification of new materials with improved properties.3 Since the overall OSC efficiency depends on the rates of several elementary charge transfer processes which can take place at the donor/acceptor (D/A) interface (e.g. photoinduced hole and electron transfer, excitation energy transfer, and charge recombination), reliable and fast protocols for evaluating such rates from first principles are needed. Herein, we present a protocol4 where Fermi’s Golden Rule rates for the processes occurring at the interface are computed on a reliable morphology obtained through molecular dynamics simulations using quantum-mechanically derived force fields. This protocol is then applied to predict and compare the performances of different BHJ blends, focusing on particular on the sources of energy losses, a problem of outstanding importance for increasing power conversion efficiency.
Theoretical Nanoscale Framework for Reliable Prediction of Organic Solar Cell Efficiency
Alessandro Landi
;Andrea Peluso
2025
Abstract
Organic solar cells (OSCs) offer significant advantages over traditional silicon devices, because of their lower costs, easier processability, improved mechanical properties, and chemically-tuneable electronic properties.1 The identification of novel donors and acceptors boosted up the power conversion efficiency (PCE) up to 19% for bulk heterojunction (BHJ) OSC;2 however, this value is still lower than their inorganic counterparts, thus hindering their commercialization. Theoretical studies have the potential to play a key role in the quest for higher PCE, by unravelling structure-property relations which can lead to the identification of new materials with improved properties.3 Since the overall OSC efficiency depends on the rates of several elementary charge transfer processes which can take place at the donor/acceptor (D/A) interface (e.g. photoinduced hole and electron transfer, excitation energy transfer, and charge recombination), reliable and fast protocols for evaluating such rates from first principles are needed. Herein, we present a protocol4 where Fermi’s Golden Rule rates for the processes occurring at the interface are computed on a reliable morphology obtained through molecular dynamics simulations using quantum-mechanically derived force fields. This protocol is then applied to predict and compare the performances of different BHJ blends, focusing on particular on the sources of energy losses, a problem of outstanding importance for increasing power conversion efficiency.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
