Graphite/Carbon Black Counter Electrode Deposition Methods to Improve the Efficiency and Stability of Hole-Transport-Layer-Free Perovskite Solar Cells

Abstract

The interfacial compatibility between the graphite/carbon black composite counter electrode (Gr/CB CE) and the perovskite layer is a crucial determinant of the performance of the hole-transport-layer-free carbon-based perovskite solar cells, and judicious selection of the Gr/CB CE application method is essential for achieving an optimum contact. In this work, three different types of Gr/CB CEs application methods are investigated: (1) deposition of Gr/CB on the fluorine-doped tin oxide (FTO) substrate, followed by clamping to the perovskite layer, (2) direct deposition of Gr/CB onto the perovskite layer, and (3) deposition of Gr/CB onto the PbI 2 precursor layer, followed by immersion in methylammonium iodide solution for the in situ conversion of PbI 2 to perovskite. The results revealed that Method 3 produced superior Gr/CB–perovskite contacts, resulting in up to 8.81% power conversion efficiency. The devices prepared using Method 3 also exhibited the best stability in the air, retaining 71.1% of their original efficiency after 1600 h of continuous testing. These results demonstrate that Gr/CB CEs can be considered excellent alternatives to the costly noble metals often employed in perovskite solar cells (PSCs) when deposited using a suitable technique.

Self-Assembled Conjugated Small Molecular Electrolytes for the Formation of an Electron Transporting Layer via Single-Step Solution Processing for BHJ Solar Cells

“…The value of R3 stands for the carrier transport resistance, which is related to the interfacial resistance between the active layer and ETLs. Obviously, there’s negligible difference of the R1 value of each CSME-modified device, which indicated the formation of the CSME layer between ITO and active layer. − In addition, the R3 value is in the order of IcL4N (200.10 Ω) > IcL10N (199.90 Ω) > IcL6N (182.40 Ω) > IcL8N (180.80 Ω) > IcB8N (149.50 Ω), which is consistent well with the trend of FF values in J–V characteristics curves. We also performed TEM, as shown in Figure S11.…”

Self‐Encapsulable Carbon Electrode for Efficient and Stable Perovskite Solar Cells

“…Overall, large graphite particles were decorated with nanometer‐sized carbon black particles, which is a common morphological characteristic observed from the graphite/carbon black‐based electrode slurry for secondary batteries. [ 87,88 ] Addition of PIB did not alter homogenous dispersion of graphite and carbon black particles. Graphite and carbon black particles kept up their interconnections even after the PIB portion was raised from 8:1:1 to 8:1:4.…”

Influence of metal salts (Al, Ca, and Mg) on the work function and hole extraction at carbon counter electrodes in perovskite solar cells

“…In addition, the hydrophobicity, chemical inertness, and typically high thickness of carbon layers employed as CEs mean that the carbon layer can serve as a barrier to prevent water from accessing the perovskite layer [ 11 , 12 ]. Motivated by these characteristics, extensive research has been conducted on carbonaceous materials, including carbon black [ [13] , [14] , [15] ], carbon nanotubes [ 16 , 17 ], carbon ink [ 18 ], commercial carbon paste [ 19 ], spongy carbon [ 20 ], and graphite [ 21 , 22 ], as replacement for expensive HTMs and noble metal CEs.…”