Side‐Chain Methylthio‐Based Position Isomerism of Hole‐Transport Materials for Perovskite Solar Cells: From Theoretical Simulation to Experimental Characterization

Abstract

Hole transporting materials (HTMs) are imperative for promoting the development of perovskite solar cells (PSCs). Herein, three isomers of RQ4, RQ5, and RQ6 are constructed by methylthio (-SMe) group in the para, meta, and adjacent sites of terminal benzene on the side-chain of carbazole-arylamine derivatives based HTMs, and investigated by means of the theoretical simulation and experimental characterization. As a result of the theoretical simulation, the isomeric HTMs of RQ4-RQ6 exhibit appropriate highest occupied molecular orbital /lowest unoccupied molecular orbital energy levels and good optical properties. However, by comparison with RQ4 and RQ5, a better planar configuration and closer molecular stacking for RQ6 may be beneficial to promote the hole coupling, interface interaction, and charge transfer at perovskite/HTMs interface. In order to verify the accuracy of the theoretical model, the designed RQ4-RQ6 are synthesized to be used to assemble PSCs devices. In comparison to isomers RQ4 (20.07%) and RQ5 (18.18%) based devices, the RQ6 based devices has higher power conversion efficiency of 21.03% because of its high hole mobility, the film formation ability, and large charge transfer at perovskite/HTMs interface. The experimental results confirm the reliability of the theoretical simulation and provide an effective strategy to obtain potential HTMs through isomerization of side-chain functional groups.

Theoretical calculations and experimental investigation toward the π-conjugated modulation in arylamine derivative-based hole transporting materials for perovskite solar cells

“…In our previous works, the B3P86/6-311G(d,p) method output a credible HOMO level in comparison with the experimental results. 46,47 According to Fig. 2c and d, it was found that the contribution of the LUMO for the pyrene group of CY2 (99.16%) was larger than that for the naphthalene group of CY1 (97.43%).…”

Dopant‐Free Pyrene‐Based Hole Transporting Material Enables Efficient and Stable Perovskite Solar Cells

“…The dense and uniform morphology of the Py-DB film is beneficial for interfacial contact, and thus could facilitate charge transfer at the perovskite/HTM interface. [36][37]…”

Benzodithiophene‐Thienothiadiazole Copolymers as Dopant‐Free Hole‐Transporting Layers Enabling Efficient and Stable Perovskite Solar Cells

“…Although the PCE of the champion device was not as good as the device based on the traditionally doped spiro-OMeTAD (Figure S10, Supporting Information), the over 22% efficiency was in the top-performing levels for normal structured devices based on dopant-free HTMs reported to date (Table S1, Supporting Information). [14][15][16][17][18][19]24,39,[46][47][48][49][50][51] To confirm the reliability of our sunlight simulator, external quantum efficiency (EQE) spectra were collected (Figure 4c). Both devices showed similar EQE response and high EQE value in the range of 350-800 nm.…”