Assessing the energy offset at the electron donor/acceptor interface in organic solar cells through radiative efficiency measurements

Abstract

The radiative efficiency of non-fullerene devices is modulated by the energy offset, making electroluminescence a powerful tool for energy offset evaluation.

Enhanced and Balanced Charge Transport Boosting Ternary Solar Cells Over 17% Efficiency

“…The optimal PM6:Y6 binary device exhibits a V oc of 0.84 V, a J sc of 24.25 mA cm −2 , and an FF of 0.795, yielding a PCE of 16.19%, in line with previous report. [11,26] By contrast, the binary device based on DRTB-T-C4:Y6 has a poor PCE of 4.14% with a V oc of 0.90 V, a J sc of 10.93 mA cm −2 , and an FF of 0.42. When increasing the content of DRTB-T-C4 by 10% (in donors w/w) into the host PM6:Y6 blend, the resulting ternary device produces the PCE of 17.13%, accompanied with a V oc of 0.85 V, a J sc of 24.79 mA cm −2 , and an FF of 0.813, which is one of the best efficiencies for the ternary OSCs reported to date.…”

“…[20,21] Blend morphologies that possess fine phase separation and molecular packing can create highly effective charge transfer networks in the ternary system, resulting in improved charge transport and thus high device FF. [11,[22][23][24] Ternary architecture is one of the most effective strategies to boost the power conversion efficiency (PCE) of organic solar cells (OSCs). Here, an OSC with a ternary architecture featuring a highly crystalline molecular donor DRTB-T-C4 as a third component to the host binary system consisting of a polymer donor PM6 and a nonfullerene acceptor Y6 is reported.…”

“…[5][6][7][8] To further improve the PCEs, so-called ternary OSCs that integrate two donors and one acceptor or one donor and two acceptors into a photoactive layer, have been established to enhance the light harvesting, while the ternary devices retain the simplicity of fabrication process of the normal binary devices. [9][10][11][12] The PCEs of the OSCs are determined by the three photovoltaic parameters including open-circuit voltage (V oc ), shortcircuit current density (J sc ), and fill factor (FF). Generally, there is the trade-off between V oc and J sc because of the correlation…”

“…Recently, a new NFA semiconductor abbreviated as Y6 was reported to yield a breakthrough PCE of over 16% in combination with a polymer donor named PM6. [11,[25][26][27][28] The PM6:Y6 blend exhibits barrierless free charge generation with low recombination, regardless of excitation energy, rendering it a high-performance binary system. [29] In this work, we incorporated a second donor DRTB-T-C4 into the host PM6:Y6 blend to construct ternary OSCs and obtained a very impressive PCE of 17.13% with a V oc of 0.85 V, a J sc of 24.79 mA cm −2 , and an FF of 0.813.…”

Improved Average Figure‐of‐Merit of High‐Efficiency Nonfullerene Solar Cells via Minor Combinatory Side Chain Approach

“…In addition, based on the Shockley-Queisser theory, the maximum theoretical PCE for BHJ OSCs has been predicted up to 30%. [60][61][62] Empirically, the ideal active layer with an ASC of 40% could be achievable so that a theoretical AFOM of 1.33 could be deduced. Currently, the average evaluation manifests that a proper low-SC acceptor component plays an important role in achieving a good costeffectiveness for organic photovoltaic application.…”