Backbone Engineering with Asymmetric Core to Finely Tune Phase Separation for High-Performance All-Small-Molecule Organic Solar Cells

Abstract

In order to obtain high-performance all-small-molecule organic solar cells (ASM-OSCs), it is crucial to exploit the available strategy for molecular design and to further understand key structure–property relationship that can rationally control the blend nanomorphology and influence the physical process. In this work, we design two small molecule donors FBD-S1 and TBD-S2 with identical electron-withdrawing units but various asymmetric central cores, which exhibit differing phase separation in Y6-based blend films. It is found that TBD-S2 with increased phase separation between donor and acceptor can lead to more favorable interpenetrating networks, effective exciton dissociation, and enhanced and more balanced charge transport. Importantly, a remarkable PCE of 13.1% is obtained for TBD-S2:Y6 based ASM-OSCs, which is an attractive photovoltaic performance for ASM-OSCs. This result demonstrates that the central core modification at the atomic level for small molecule donors can delicately control the phase separation and optimize photophysical processes, and refines device performance, which facilitate development in the ASM-OSC research field.

π‐Extended Conjugated Polymer Acceptor Containing Thienylene–Vinylene–Thienylene Unit for High‐Performance Thick‐Film All‐Polymer Solar Cells with Superior Long‐Term Stability

“…In comparison with that of JD40:PJTET device, the more than twice charge extraction rate of JD40:PJTVT device is likely to be one of the main reasons for the enhancement of photocurrent and FF. [ 47–49 ] Overall, the highly effective conversion of light into the photocurrent can be afforded with suppressed trap assisted recombination, improved charge extraction, and more balanced charge‐transport properties by simply substituting the TET linking unit for π‐extended TVT unit to tune the phase separation and molecular packing, being ultimately embodied in the observed improvement of J SC and FF.…”

A New Alcohol‐Soluble Polymer PFN‐ID as Cathode Interlayer to Optimize Performance of Conventional Polymer Solar Cells by Increasing Electron Mobility

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] To date, many attempts have been made to obtain efficient PSCs and a lot of effort has been put into them, including interfacial engineering, study of novel donor/acceptor materials, and optimizing the morphology. [19][20][21][22][23][24][25][26][27][28][29][30][31][32] By now, the power conversion efficiency (PCE) of PSCs has exceeded 19%. [33] During the development of PSCs, interfacial engineering has received a lot of attention for its ability to improve the photovoltaic parameters of PSCs and thus improve PCE.…”

“…[ 1–18 ] To date, many attempts have been made to obtain efficient PSCs and a lot of effort has been put into them, including interfacial engineering, study of novel donor/acceptor materials, and optimizing the morphology. [ 19–32 ] By now, the power conversion efficiency (PCE) of PSCs has exceeded 19%. [ 33 ]…”

Enhancement Efficiency of Organic Photovoltaic Cells via Green Solvents and Nontoxic Halogen‐Free Additives

“…Organic photovoltaic cells with an interpenetrating network structure consisting of a donor and an acceptor, also known as bulk heterojunctions (BHJs), play an important role in converting light energy into electricity. Due to its unique advantages, such as large‐scale manufacturing, lightweight, flexibility, and so on, [ 1–21 ] it can be an alternative to inorganic solar cells. To enhance device performance, it is crucial to refine the morphology of photoactive layer and the optimal morphology must have the following characteristics of a fine bicontinuous interpenetrating network and suitable phase separation size and purity.…”