Bridging the Buried Interface with Piperazine Dihydriodide Layer for High Performance Inverted Solar Cells

Abstract

comparison to stability between both kinds of solar cells, we might soberly conceive that there is still an immense challenge for the operation lifetime of PSCs. [8][9][10][11] Up to this point, significant attempts have been made to increase the stability of PSCs using multiple-faceted tactics such as adjusting the components of perovskite precursor (methylammounium(MA)free, inorganic or low dimensional materials), [12][13][14] developing additive engineering or passivation agents, [15,16] exploring novel fabrication strategies (liquid medium annealing and mechanical or chemical polishing) and replacing the charge transport layer with robust materials. [17][18][19] These methods have shown significant improvement in curbing the defects located at the grain boundaries or surface and consolidating the structure of perovskite film. However, the stability of PSCs is not yet at the level needed to open the commercial door, therefore further exploration of alternative approaches is needed before perovskite solar cells may enter the mainstream. As for the solution deposition process of perovskite films, the perovskite-substrate interface intimately affects perovskite crystallization, interface defects, and residual strain, which play a key role in fabricating high-quality perovskite films as well. Additionally, it is known that the buildup of deep-level trap states causes undesired non-radiative losses to occur at the interfaces with bottom contact layers, resulting in reduced device power outputs. [20,21] However, compared with the indepth study on the top interface, exploring the degradation process of the buried side of perovskite film from the morphology and photo-electronics aspects is relatively complicated and scanty owing to non-exposed features. [22,23] Recent studies illustrate the formation of a large number of 3D voids at the imbedded interface of perovskites and hole transport layer in p-i-n-structured solar cells. [24,25] These unfavorable voids are attributed to the inadequate evaporation of the entrapped nonvolatile solvent additives, such as dimethyl sulfoxide (DMSO), resulting in defect densities ascending of roughly two orders of magnitude compared with the center of the perovskite film. [25,26] Under illumination testing, perovskite solar cells start to deteriorate at the interfacial regions between perovskites and charge transport layers. [23] Yang et al. established the microstructure-property relations for uncovering the basic Given that it is closely related to perovskite crystallization and interfacial trap densities, buried interfacial engineering is crucial for creating effective and stable perovskite solar cells. Compared with the in-depth studies on the defect at the top perovskite interface, exploring the defect of the buried side of perovskite film is relatively complicated and scanty owing to the non-exposed feature. Herein, the degradation process is probed from the buried side of perovskite films with continuous illumination and its effects on morphology and photoelectronic characteris...

Key Roles of Interfaces in Inverted Metal-Halide Perovskite Solar Cells

“…Also, the intermediate PDI 2 buffer layer reduces the adhesion of PTAA substrate, and the system adapts itself to the lattice mismatch between the perovskite and the substrate, thus forming a voids-free buried interface (Figure 17c−f). 219 In other words, the active Ni ≥3+ ions on the NiO x surface are effectively suppressed by this method, and the cavity extraction capacity is greatly improved. Moreover, the perovskite films formed on the BDT-POZ-modified NiO x showed a smoother and more uniform surface and no pinholes than a standard NiO x HTL.…”

Microstress for metal halide perovskite solar cells: from source to influence and management

“…8f). Liang et al 101 introduced a piperazine dihydrotriamine (PDI 2 ) buffer layer between PTAA substrate and the perovskite. The PDI 2 buffer layer can promote the matching of thermal expansion between the perovskite and the substrate, resulting in a decrease in the adhesion of the PTTAA substrate, and promote the matching of the PTAA substrate with the perovskite lattice, resulting in the release of the lattice strain, thus forming a void-free buried interface.…”

Recent Advancements in Enhancing Interfacial Charge Transport for Perovskite Solar Cells

“…Therefore, with the benefits of a favorable interface and defect passivation under the (P3CT-BN) buffer layer, the hole transport ability of P3HT is enhanced, resulting in an increase in PCE% from 13.13% to 19.23%. Qi Song et al [147] recently reported that the PCE of PSCs was improved to 23.42% by adding a buffer layer comprised of piperazine dihydride (PDI 2 ) at the embedded bottom interface (Figure 8c). The PDI 2 buffer layer proved effective in addressing the thermal expansion mismatch between the perovskite layer and the substrate coated with PTAA HTL.…”

“…Reproduced with permission. [147] Copyright 2023, Wiley. d) Energy level alignment diagram for PSCs with and without KBr buffer layer modification, and the PL spectra for various concentration KBr buffer layer modification.…”