36% Enhanced Efficiency of Ternary Organic Solar Cells by Doping a NT-Based Polymer as an Electron-Cascade Donor

Abstract

In recent years, ternary organic photovoltaic cells (OPVs) have been dedicated to improving power conversion efficiency (PCE) by broadening optical absorption spectra. Ternary OPVs with different poly[thieno[3,2-b]thiophene-2,5-diyl-alt-4,9-bis(4-(2-decyltetradecyl)thien-2-yl)naphtho[1,2-c:5,6-c’]bis[1,2,5]thiadiazole-5,5′-diyl] (PTT-DTNT-DT) doping concentrations were designed and the effect of PTT-DTNT-DT as a complementary electron donor on the performance of OPVs was investigated. The optimized PCE of OPVs was increased from 3.42% to 4.66% by doping 20 wt % PTT-DTNT-DT. The remarkable improvement in the performance of the ternary device is mainly attributed to the sharp increase in the short-circuit current density and fill-factor. The major reasons have been systematically studied from atomic force microscopy, electrochemical impedance spectroscopy, surface energy, space charge limited current and photocurrent behavior. It has been found that the separation of excitons and the transportation of charge are enhanced while light absorption is increased, and the charge recombination also decreases due to the optimization of the cascade energy level and the morphology of the ternary active layer. The results show that it is feasible to improve the performance of ternary OPVs by their complementary absorption.

Comparative Investigation of Fullerene PC71BM and Non-fullerene ITIC-Th Acceptors Blended With P3HT or PBDB-T Donor Polymers for PV Applications

“…In the past decade, bulk heterojunction (BHJ) organic solar cells (OSCs) have been intensively studied for their high potential for realizing environmentally friendly, low cost, noncomplex, and flexible large area devices (Zhou et al, 2012;Liu et al, 2015). Despite the rapid improvement in the power conversion efficiency in the recent past, the progress toward commercialization of these devices is still hindered by their low carrier mobility, insufficient photoabsorption (Li et al, 2018), and degradation by intrinsic factors such as inter-layer molecular cross diffusion. Additionally, external factors such as moisture and photo-oxidation have been found to affect device stability (Zakhidov et al, 2020).…”

Improved Performance of Ternary Solar Cells by Using BODIPY Triads

“…The EIS spectra were fitted by using an equivalent circuit model, as shown in the inset of Figure 5. R s , R rec , and CPE represented the series resistance, the charge recombination resistance, and the constant phased element representing the chemical capacitance, respectively [60,61]. Figure 5 showed Nyquist plots of binary solar cells and ternary solar cells under 1 sun simulation.…”

Improvement of Exciton Collection and Light-Harvesting Range in Ternary Blend Polymer Solar Cells Based on Two Non-Fullerene Acceptors

“…In most cases, it is desirable to keep the ratio of donor to acceptor in the ternary blend the same as that in the optimized binary blend cell because the hole and electron transport would be balanced. In other words, with increasing weight ratio of the third component, the photon harvesting of the original component should decrease [35][36][37][38][39]. For polymer/fullerene solar cells, such a trade-off relation has been overcome by efficient energy transfer, which improves the exciton harvesting in ternary blend solar cells [24,25,28,40].…”