Organic Ligand‐Free ZnO Quantum Dots for Efficient and Stable Perovskite Solar Cells

Abstract

Zinc oxide (ZnO) is a promising electron‐transport layer (ETL) in thin‐film photovoltaics. However, the poor chemical compatibility between commonly used sol–gel‐derived ZnO nanostructures and organo–metal halide perovskites makes it highly challenging to obtain efficient and stable perovskite solar cells (PSCs). Here, a novel approach is reported for low‐temperature processed pure ZnO ETLs for planar heterojunction PSCs based on ZnO quantum dots (QDs) stabilized by dimethyl sulfoxide (DMSO) as easily removable solvent molecules. With no need for the ETL doping or surface modification, the champion PSC comprising the mixed‐cation and mixed‐halide Cs5(MA0.17FA0.83)95Pb(I0.83Br0.17)3 absorber layer reaches a maximum power conversion efficiency of 20.05%, which is significantly higher than that obtained for a reference device based on a standard sol–gel‐derived ZnO nanostructured layer (17.78%). Thus, along with the observed better operational stability in ambient conditions and elevated temperature, the champion device achieves the state‐of‐the‐art performance among reported non‐passivated pure ZnO ETL‐based PSCs. The improved photovoltaic performance is attributed to both a higher uniformity of the surface morphology and a lower defects density of films based on the organometallic‐derived QDs that are likely to ensure the enhanced stability of the ZnO/perovskite interface.

Secured Nanosynthesis–Deposition Aerosol Process for Composite Thin Films Incorporating Highly Dispersed Nanoparticles

“…[ 37 , 38 , 39 , 40 ] The formation of ZnO NPs by this approach is highly appealing as ZnO NPs present wide technological applications due to their unique properties. These include electro‐optical properties, [ 41 , 42 ] which can be used in devices such as ultraviolet (UV) light‐emitting diodes (LEDs), [ 42 , 43 ] blue luminescent devices or UV lasers [ 44 ] ; photo(electro)catalytic water treatment, [ 45 , 46 , 47 ] antibacterial agents, [ 48 , 49 ] solar cells, [ 50 , 51 , 52 , 53 , 54 ] and others. [ 55 , 56 ] Such unique properties require not only the ZnO material to be nanosized, but also to be homogeneously dispersed without agglomeration.…”

Probing the Low-Frequency Response of Impedance Spectroscopy of Halide Perovskite Single Crystals Using Machine Learning

“…Metal halide perovskites (MHPs) have emerged as a promising candidate to outgrow the Si-based materials in the field of photovoltaics. − Despite the progress in improving the power conversion efficiency (PCE) of the so-called perovskite solar cells (PSCs), − some open questions still remain to be solved. , Particularly, further improvement in operational stability of PSCs requires in-depth understanding of their fundamental degradation processes . In this context, electrochemical impedance spectroscopy (EIS) is an appealing technique to study MHPs and related devices. , However, the utilization of EIS especially in understanding various processes occurring in PSCs lags behind compared to dye-sensitized solar cells (DSSCs) .…”

A modular design approach to polymer-coated ZnO nanocrystals

“…organometallic-derived ZnO NCs have appeared relatively bio-safe, 35 prone to the ligand shell functionalization using the classic copper(I)-catalyzed click chemistry with the preservation of their photoluminescence properties, 36 and highly prospective for applications in photocatalysis 37 and photovoltaics as very effective electron transport material for perovskite solar cells. 38 In turn that examples of nanocomposites involving ZnO NCs derived from an organometallic method are still scant. 11 , 32 , 33 …”