The Effect of Donor and Nonfullerene Acceptor Inhomogeneous Distribution within the Photoactive Layer on the Performance of Polymer Solar Cells with Different Device Structures

Abstract

Due to the inhomogeneous distribution of donor and acceptor materials within the photoactive layer of bulk heterojunction organic solar cells (OSCs), proper selection of a conventional or an inverted device structure is crucial for effective exciton dissociation and charge transportation. Herein, we investigate the donor and acceptor distribution within the non-fullerene photoactive layer based on PBDTTT-ET:IEICO by time-of-flight secondary-ion mass spectroscopy (TOF-SIMS) and scanning Kelvin probe microscopy (SKPM), indicating that more IEICO enriches on the surface of the photoactive layer while PBDTTT-ET distributes homogeneously within the photoactive layer. To further understand the effect of the inhomogeneous component distribution on the photovoltaic performance, both conventional and inverted OSCs were fabricated. As a result, the conventional device shows a power conversion efficiency (PCE) of 8.83% which is 41% higher than that of inverted one (6.26%). Eventually, we employed nickel oxide (NiO x ) instead of PEDOT:PSS as anode buffer layer to further enhance the stability and PCE of OSCs with conventional structure, and a promising PCE of 9.12% is achieved.

Recent progress in cathode interlayer materials for non‐fullerene organic solar cells

“…The improved efficiency was ascribed to the lower work function of ZnO/SAM which efficiently extract electron toward the cathode. Thermodynamically, the surface free energy of the interlayer has a significant impact on the morphology of the BHJ layer, as a result, organic acceptor enriches on the air‐interface which is favorable for the improvement of NF‐OSCs 218 . Inspired by this, recently Zhu et al 219 inserted glycine on the top of ZnO CIL as a surface modifier that had a carboxyl group.…”

“…Thermodynamically, the surface free energy of the interlayer has a significant impact on the morphology of the BHJ layer, as a result, organic acceptor enriches on the air-interface which is favorable for the improvement of NF-OSCs. 218 Inspired by this, recently Zhu et al 219 inserted glycine on the top of ZnO CIL as a surface modifier that had a carboxyl group. Due to the chemical interaction of ZnO with glycine, the reduced work function from 4.1 to 4.0 eV, and fewer defect states were observed.…”

Improving Photovoltaic Properties of P3HT:IC60BA through the Incorporation of Small Molecules

“…to accentuate the efficiency of BHJ PSCs [ 18 ]. The functional roles of the selected additives, such as their boiling point, and the nature of their interaction with the donor or acceptor in the photoactive blend, play key roles in the nanomorphology, crystallinity of the components, mobility, photocurrent, and PCE of the PSC [ 19 , 20 ]. A literature search reveals that the exploration of functional additives to optimize the morphology of the bis-adduct fullerene-based binary systems and optoelectronic properties has only sporadically been reported, and hence is worthy of in-depth investigation [ 21 , 22 ].…”

Improved UV sensitivity and charge transport in PTB7-Th:PC71BM solar cells doped with cadmium selenide quantum dots

“…The surface potential of the sample is defined as the following eqn (1). 18,19 where SP is the acronym of surface potential, V dc is the DC voltage, q is the electron charge, φ tip and φ sample are the work functions of the tip and the sample, respectively. Fig.…”