Simultaneously Decreasing the Bandgap and V_oc Loss in Efficient Ternary Organic Solar Cells

Abstract

Ternary architecture is a promising strategy to further boost the performance of organic solar cells (OSCs). Reducing the bandgap of the active layer materials not only widens the absorption wavelength range and enhances the short‐circuit current (Jsc) of the OSC, but also decreases the open‐circuit voltage (Voc) of the device, leading to a trade‐off situation for the optimization of the material system. Herein, a small‐molecule donor BTID‐2F, featuring a narrower bandgap than that of PM6, is introduced into a PM6:Y6 based system. The redshift in external quantum efficiency indicates the narrower bandgap and better aggregation in the ternary blends than those of binary ones. Interestingly, lower energy disorder and energy loss are also attained for the ternary devices, leading to higher Voc. Furthermore, owing to the suppressed recombination and morphological optimization, a simultaneous enhancement in the Jsc and fill factor boosts the power conversion efficiency (PCE) of ternary OSC to 17.9% compared to 16.62% for the binary device. Likewise, replacing the acceptor with the L8‐BO molecule further improves the ternary PCE to 18.52%. This work indicates an emerging approach for fabricating high‐performance ternary OSCs with a decreased bandgap and increased Voc.

Regulation of Polymer Configurations Enables Green Solvent‐Processed Large‐Area Binary All‐Polymer Solar Cells With Breakthrough Performance and High Efficiency Stretchability Factor

“…The V loss could be divided into three parts: 1) ΔE CT , stipulated as the energy difference between the locally excited state (S 1 ) of the acceptors or donors; 2) ΔV rad , the radiative recombination voltage loss; 3) and ΔV non-rad , the non-radiative recombination voltage loss. [41][42][43][44] According to the Marcus theory, [45] Figure 2g,h determines the E CT by fitting the lower energy part of the sensitive external quantum efficiency (sEQE) spectrum and the higher energy part of the EL spectra. In addition, the EQE EL was also obtained in Figure S8b, Supporting Information.…”

Controlling Morphology and Voltage Loss with Ternary Strategy Triggers Efficient All-Small-Molecule Organic Solar Cells

“…The innovation of organic photovoltaic materials has always been the most visible and effective method to break through the bottleneck of efficiency in the development history of OSCs. − Employing advisible optimization strategies to unlock the full potential of donors and acceptors is a necessary process for realizing efficient OSCs. The traditional optimization techniques, such as solvent/solid additives and solvent-vapor/thermal annealing, have been well demonstrated to be effective approaches for enhancing charge generation and extraction by regulating the molecular distribution and arrangement, while they are powerless to reduce the voltage loss of the OSCs. − The ternary strategy can gather multiple superiorities in one matrix via incorporating a complementary third component with the binary host system, which is also easy to combine with traditional optimization techniques due to the retentive single-junction device structure. − Introducing the third component with suitable energy levels and bandgap possesses the potential to decrease voltage loss of OSCs. Moreover, the appropriate compatibility can provide the possibility to modulate film morphology and then promote charge production and transport, which has already been certified in various types of OSCs. − Considering the above analyses, the ternary tactic could be a potential thoroughfare to simultaneously control the sensitive morphology and voltage loss for realizing efficient ASM-OSCs.…”

End‐Group Engineering of Chlorine‐Trialkylsiylthienyl Chain‐Substituted Small‐Molecule Donors for High‐Efficiency Ternary Solar Cells

“…[12][13][14] Despite the remarkable achievements, the development of binary OSCs is still limited by some intrinsic shortcomings, particularly the trade-off between the current density (J SC ) and V OC . [2,15,16] For instance, the initially designed lowbandgap material Y6 can deliver a high J SC for PM6:Y6 binary device, yet result in a relatively low V OC , [17][18][19] consequently hindering the further enhancement of device performance. In this regard, the fabrication of ternary OSCs by incorporation of a third component into the binary system offers a facile and effective approach to solve this issue.…”

“…Moreover, since the long-term stability of OSCs has been recognized the biggest challenge for future commercialization, the introduction of an appropriate third component has been proven to enhance the stability of the devices. [19,30,31] It is worth mentioning that most of the third components in ternary OSC are fullerenes and nonfullerene acceptors so far. [32,33] Recently, SM donors have attracted extensive research attention as the third compound due to their definite molecular structure, simple synthesize route, and easier purification.…”