Benzothiadiazole Containing D‐π‐A Conjugated Compounds for Dye‐Sensitized Solar Cells: Synthesis, Properties, and Photovoltaic Performances

Abstract

Two D-pi-A conjugated molecules, BzTCA and BzTMCA, were developed through facile synthetic approaches for dye-sensitized solar cells. The investigation of the photophysical properties of BzTCA and BzTMCA both in dilute solutions and in thin films indicates that their absorption exhibits a wide coverage of the solar spectrum. The absorption features for BzTCA and BzTMCA commence at about 710 nm in solution, and at about 800 nm in the solid state. The absorption maxima (lambda(max)) for both BzTCA and BzTMCA on TiO(2) film are almost the same as those in dilute solution. Their HOMOs and LUMOs were found to partly overlap at the center of these dyes, which guarantees appreciable interactions between the donors and acceptors. The investigation of the performance of dye-sensitized solar cells fabricated from BzTCA and BzTMCA indicated that the power-conversion efficiencies are 6.04 % and 4.68 %, respectively, which could be comparable with the normal sensitizer N3. BzTMCA showed lower incident photon-to-electron conversion efficiency (IPCE) and J(sc) values relative to BzTCA, which is probably because of the weaker driving force of dye regeneration and electron injection process of BzTMCA. The IPCE responsive area reached nearly 800 nm, which provides great potential for further improvement of the photocurrent density and power-conversion efficiency. Our investigations demonstrate that both dyes BzTCA and BzTMCA could be promising candidates for dye-sensitized solar cells.

Hexylthiophene‐Featured D–A–π–A Structural Indoline Chromophores for Coadsorbent‐Free and Panchromatic Dye‐Sensitized Solar Cells

“…Thus, compared with WS-2 or WS-6, the oxidized WS-11, formed after electron injection, will be less efficiently reduced to the neutral state due to the insufficient regeneration driving force. [13] To further understand why WS-11 shows low J sc , Density Functional Theory (DFT) analysis was supplemented as shown in SI, Figure S7. The calculated HOMO for WS-11 is indeed higher than WS-2 and WS-6, which is unfavorable for dye regeneration (SI , Table S1).…”

“…Such a synthetic procedure for WS-6 and WS-11 was optimized on the basis of reaction selectivity and product yields. The chemical structures of important aldehyde intermediates and final dyes were fully characterized with 1 H NMR, 13 C NMR, and HRMS (see Experimental Section).…”

Carbazole-functionalized polyphenylene-decorated solid state emissive D–A–D molecules: reduced donor–acceptor interaction and enhanced emission in the solid state

“…The major challenge in developing luminescent materials with D-A systems is to prevent the large red shift in emission and ACQ in solid state while preserving the merits of the D-A architecture. [15][16][17][18][19]6 However, it is very hard to get higher solid-state efficiencies than those of molecularly dissolved species in non polar solvents. [20][21] Many methods have been adopted to reduce ACQ like doping method, introduction of π spacer, using weak π donor/weak π acceptor etc but they have met with limited success only.…”

Significant Improvement of Dye‐Sensitized Solar Cell Performance by Small Structural Modification in π‐Conjugated Donor–Acceptor Dyes

“…For this purpose, various low bandgap sensitizers for DSSCs have been prepared by implementing, e.g., the electrondeficient benzothiadiazole (BTDA) unit into the bridging framework of D-π-A molecules. [10][11][12][13][14][15][16] In search of new metal-free sensitizers for DSSCs, we present new D-A sensitizers 1 and 2 that are built up by a triarylaminebithiophene donor (D) and a BTDA-substituted cyanoacrylic…”