Kinetics versus Energetics in Dye-Sensitized Solar Cells Based on an Ethynyl-Linked Porphyrin Heterodimer

Abstract

Out of the scientific concern on the kinetics versus energetics for rational understanding and optimization of near-IR dye-sensitized solar cells (DSCs), an N-fused carbazole-substituted ethynyl-linked porphyrin heterodimer (DTBC) reported previously by our group was focused upon in terms of photovoltaic, photoelectrochemical, and steady-state and time-resolved photophysical properties in varied electrolyte environments. A primitive attempt to balance the photocurrent against the photovoltage by varying the concentration of the common coadsorbent 4-tert-butylpyridine (TBP) revealed that TBP continuously suppressed injection but provided inadequate compensation in open-circuit voltage (V oc). This further drew out the perspective of the widely ignored dye–electrolyte interaction in DSCs, specifically the axial coordination of TBP to the central zinc cation in porphyrin sensitizers that may retard electron injection. As an alternative, a TBP-free electrolyte containing guanidinium thiocyanate was developed to realize greatly promoted V oc with little current sacrifice, thus significantly enhancing overall energy conversion efficiencies. The excited state was protracted to counteract the injection retardation caused by much reduced driving force, setting a successful example of bilateral compromise between kinetics and energetics in near-IR DSCs.

Efficient Solar Cells Sensitized by Porphyrins with an Extended Conjugation Framework and a Carbazole Donor: From Molecular Design to Cosensitization

“…Thus, the highest cell efficiency of 10.45 % was achieved. This value is higher than that obtained for the ruthenium dye N71919 (Table 1), and significantly higher than the best efficiency of 5.74 % previously reported for porphyrin dyes containing a carbazole donor 12f. In conclusion, this work provides an effective combined strategy of molecular design and cosensitization for developing efficient DSSCs.…”

“…Thus the onset wavelength of its absorption was extended from λ =655 nm to 695 nm, but the cell efficiency was decreased from 5.51 % to 2.22 % 11. For porphyrin sensitizers containing a carbazole donor,11,12 the highest efficiency is 5.74 %,12f which is slightly higher than that for Q2 , but much lower than the value of 12.5 % reported for the non‐porphyrin carbazole‐containing dye ADEKA‐1 13. This large difference prompted us to develop efficient porphyrin sensitizers with a carbazole donor through molecular design with focus on extending the π‐conjugated framework in combination with multiple anti‐aggregation approaches.…”

Upconversion 32Nb2O5–10La2O3–16ZrO2 glass activated with Er3+/Yb3+ and dye sensitized solar cell application

“…Upconversion luminescence spectra were recorded by a spectrofluorometer (Fluorolog-3, Jobin Yvon, Paris, France) excited by a diode laser with 980 nm continuous wave (0.5-1500 mW power was used). The DSSC equipped with bulk niobium pentoxide upconversion glass was synthesized according to the procedure reported previously [27] and the whole device is shown in Fig. 9.…”

Synthesis of 8-Aryl-O-methylcyanidins and Their Usage for Dye-Sensitized Solar Cell Devices

“…We prepared the DSSCs according to the method reported by Liu et al with slight modifications [ 28 , 38 ]. TiO 2 films for use as photoanodes were prepared by screen-printing TiO 2 pastes with different particle diameters (11–400 nm) onto F-doped SnO 2 glass.…”