Integrated manufacturing of REciclable multi-material COmposites for the TRANSport sector
High Open?Circuit Voltage Organic Solar Cells with 19.2% Efficiency Enabled by Synergistic Side?Chain Engineering
Restricted by the energy?gap law, state?of?the?art organic solar cells (OSCs) exhibit relatively low open?circuit voltage (VOC; 0.8–0.9 V) because of large nonradiative energy losses. Moreover, the trade?off between VOC and external quantum efficiency (EQE) of OSCs is more distinctive; the power conversion efficiencies (PCEs) of OSCs are still < 15% with VOCs of > 1.0 V. Herein, we carefully consider the electronic properties and aggregation behaviors of non?fullerene acceptors (NFAs) and then delicately design a new NFA (Z19) by simultaneously introducing alkoxy and phenyl?substituted alkyl chains to the conjugated backbone. Z19 exhibits a hypochromatic?shifted absorption spectrum and a high?lying LUMO energy level. Moreover, Z19 presents an ordered two?dimensional packing mode and good miscibility with polymer donor D18. The blend film exhibits suitable crystallinity and favorable phase separation with face?on dominated molecular orientation, facilitating charge transport properties. Consequently, D18:Z19 binary devices afford an exciting PCE of 19.2% (certified 18.8%) with a high VOC of 1.002 V and an EQEmax of 91.4%, much higher than for Y6?2O?based devices (PCE = 4.85%). (The latter is the highest PCE reported to date for OSCs with VOCs of > 1.0 V.) Moreover, the nonradiative energy losses of Z19?based (0.200 eV) and Y6?2O?based (0.155 eV) devices are much lower than that of Y6?based (0.239 eV) devices. Indications are that the design of such NFA organic semiconductors, considering the energy?gap law, could promote a new breakthrough in OSCs.This article is protected by copyright. All rights reserved
» Publication Date: 27/03/2024
This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement Nº 768737
