Indium Tin Oxide–Based Fully Spray‐Coated Inverted Solar Cells with Nontoxic Solvents: The Role of Buffer Layer Interface on Low‐Bandgap Photoactive Layer Performance

Abstract

In bulk heterojunction solar cells, the morphology of the interfaces between the photoactive layer (PAL) and charge transporting layers during the deposition process plays a key role in achieving high‐efficiency devices. Herein, an inverted fully spray‐coated solar cell fabricated on an indium tin oxide (ITO)‐glass substrate is presented. It is demonstrated that a spray‐coated double electron transporting layer composed of zinc oxide (ZnO) nanoparticles coated with polyethylenimine ethoxylated (PEIE) improves the morphology of the spray‐coated active layer on top of the spray‐coated cathode. Moreover, focusing on the hole transporting layer and anode, the performance obtained using a commercial poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) blend is compared with a high‐conductive anhydrous PEDOT:PSS (A‐PEDOT) mixed with a commercial PEDOT:PSS (CPP‐105D) as transporting layer. By optimizing the spray deposition of all the layers, a fully scalable spray process is used to produce polymer solar cells with ITO/ZnO/PEIE/poly[[4,8‐bis[(2‐ethylhexyl)oxy]benzo[1,2‐b:4,5‐b’]dithiophene‐2,6‐diyl] [3‐fluoro‐2‐ [(2‐ethylhexyl)carbonyl] thieno[3,4‐b]thiophenediyl]] (PTB7): [6,6]‐phenyl‐C70‐butyric‐acid‐methyl‐ester (PC70BM)/CPP:A‐PEDOT structure, achieving a power conversion efficiency (PCE) of 3.6%. Such result is significant if compared to a spray‐coated structure with evaporated anode (MoO3‐Ag). In this case (ITO/ZnO/PEIE/PTB7:PCBM/MoO3‐Ag), a power conversion efficiency of 5.5% is obtained.

Solvent-Vapor-Annealing-Induced Interfacial Self-Assembly for Simplified One-Step Spraying Organic Solar Cells

“…The highest μ e and μ h values with the most balanced μ e /μ h ratio for SVA-assisted one-step spraying fullerene- and nonfullerene-based devices make them exhibit the best device performance among all of the corresponding spraying OSCs (Figure ). The PCEs of conventional two-step spraying fullerene- and nonfullerene-based OSCs in previous reports are shown in Figure S14. ,,,,,,− It can be found that the SVA-assisted one-step spraying technique is proposed for the first time and the obtained PCEs are comparable to those of the two-step spraying OSCs reported to date because of better PFN self-assembly, finer donor–acceptor phase separation, and smoother film morphology.…”

Bio‐Derived Natural Materials Based Triboelectric Devices for Self‐Powered Ubiquitous Wearable and Implantable Intelligent Devices

“…Spray-coating has been widely used for coating transparent conductive films in the touch panel, solar cells, etc. [301][302][303][305][306][307][308][309][310][311] For instance, Girotto et al [311] utilized the spray coating of the hole-transport layer (poly(3,4ethylenedioxythiophene):poly(styrenesulfonate)) (PEDOT:PSS), electron-transport layer (poly(3-hexyl thiophene) (P3HT):C 60derivative (6,6)-phenyl C 61 -butyric acid methyl ester (PCBM) mixture) (P3HT:PCBM) for fabricating highly efficient organic solar cells with a power conversion efficiency of 3.75%. By optimizing the ink formula, the authors were able to deposit thin films with a well-defined thickness (<10 nm) and small surface roughness.…”

Indium Oxide Based Nanomaterials: Fabrication Strategies, Properties, Applications, Challenges and Future Prospect

“…Recently, the inexpensive and flexible polymer thin films with stable inorganic nanostructures as fourth generation solar cells are developed to improve the efficiency [70]. In this regard, different indium oxide based nanomaterials are used for fabrication of advanced solar cells that can efficiently convert light energy into electricity [71,72].…”