Asymmetrically Substituted 10H,10′H‐9,9′‐Spirobi[acridine] Derivatives as Hole‐Transporting Materials for Perovskite Solar Cells

Abstract

Hole-transporting materials (HTMs) based on the 10H, 10'H-9,9'-spirobi [acridine] core (BSA50 and BSA51) were synthesized, and their electronic properties were explored. Experimental and theoretical studies show that the presence of rigid 3,6-dimethoxy-9Hcarbazole moieties in BSA 50 brings about improved hole mobility and higher work function compared to bis(4-methoxyphenyl)amine units in BSA51, which increase interfacial hole transportation from perovskite to HTM. As a result, perovskite solar cells (PSCs) based on BSA50 boost power conversion efficiency (PCE) to 22.65 %, and a PSC module using BSA50 HTM exhibits a PCE of 21.35 % (6.5 × 7 cm) with a V oc of 8.761 V and FF of 79.1 %. The unencapsulated PSCs exhibit superior stability to devices employing spiro-OMeTAD, retaining nearly 90 % of their initial efficiency after 1000 h operation output. This work demonstrates the high potential of molecularly engineered spirobi[acridine] derivatives as HTMs as replacements for spiro-OMe-TAD.

Mesoscale Ordering 3D Mosaic Self-Assembly of Dopant-Free Hole Transport Material for Perovskite Solar Cells

“…Grazing incidence wide-angle X-ray scattering (GIWAXS) was used to examine the film’s relative crystallinity and molecular orientation (Figure c). The randomly oriented stack of BCzSPA is similar to that of spiro-OMeTAD, likely due to the resemblance in their steric structures . The GIWAXS patterns and corresponding line-cut profiles presented in Figure d indicate that the films display strong scattering around q = 14 nm –1 (corresponding to interplanar distances of 0.436 and 0.423 nm, D = 2π/ q z ), both in-plane and out-of-plane.…”

“…The randomly oriented stack of BCzSPA is similar to that of spiro-OMeTAD, likely due to the resemblance in their steric structures. 29 The GIWAXS patterns and corresponding line-cut profiles presented in Figure 3d indicate that the films display strong scattering around q = 14 nm −1 (corresponding to interplanar distances of 0.436 and 0.423 nm, D = 2π/q z ), both in-plane and out-of-plane. This can be attributed to amorphous electron density variations.…”

“…28 The helical orthogonal skeleton is a suitable choice for constructing 3D molecular structures, as it optimizes exciton transport pathways and mitigates molecule aggregation. 20,29 However, traditional 3D backbones composed of sp 3 carbon centers and the narrow core space of spiro-type structures lead to molecules with substantial steric hindrance and weak intermolecular interactions. 30 To address these issues, molecular mesoscale ordering is employed to balance the conflict between 3D multiarm configurations and molecular stacking.…”

“…The molecular and architectural design of OCTMs for specific device applications necessitates a deep understanding and optimization of charge transport. , Desirable OCTMs should be capable of forming long-range ordered 3D compact packings and enabling multichannel charge hopping . The helical orthogonal skeleton is a suitable choice for constructing 3D molecular structures, as it optimizes exciton transport pathways and mitigates molecule aggregation. , However, traditional 3D backbones composed of sp 3 carbon centers and the narrow core space of spiro-type structures lead to molecules with substantial steric hindrance and weak intermolecular interactions . To address these issues, molecular mesoscale ordering is employed to balance the conflict between 3D multiarm configurations and molecular stacking.…”

Peripheral substituent regulation of bias structured azulene-based hole transport materials for perovskite solar cells

“…Recently, research on HTMs with triphenylamine, carbazole, phenothiazine, phenoxazine, thiophene, and acridine as the core was extensively performed. [18][19][20][21][22][23][24][25] Most of the reported HTMs exhibit a symmetrical and unbiased molecular structure.…”