Hydrogenated TiO₂ Thin Film for Accelerating Electron Transport in Highly Efficient Planar Perovskite Solar Cells

Abstract

Intensive studies on low‐temperature deposited electron transport materials have been performed to improve the efficiency of n‐i‐p type planar perovskite solar cells to extend their application on plastic and multijunction device architectures. Here, a TiO2 film with enhanced conductivity and tailored band edge is prepared by magnetron sputtering at room temperature by hydrogen doping (HTO), which accelerates the electron extraction from perovskite photoabsorber and reduces charge transfer resistance, resulting in an improved short circuit current density and fill factor. The HTO film with upward shifted Fermi level guarantees a smaller loss on V OC and facilitates the growth of high‐quality absorber with much larger grains and more uniform size, leading to devices with negligible hysteresis. In comparison with the pristine TiO2 prepared without hydrogen doping, the HTO‐based device exhibits a substantial performance enhancement leading to an efficiency of 19.30% and more stabilized photovoltaic performance maintaining 93% of its initial value after 300 min continuous illumination in the glove box. These properties permit the room‐temperature magnetron sputtered HTO film as a promising electron transport material for flexible and tandem perovskite solar cell in the future.

Growth of Black TiO2 Quantum Dots by Solution‐Based Electrochemical Process

“…The two peaks around 464 and 458 eV, which are observed in all samples, are attributed to the Ti 4+ O bonds in TiO 2 . [ 16,17 ] Particularly, the additional 456–457 eV peaks are found only in the black TiO 2 QDs sample, which is attributed to the TiH bonds. [ 16,17 ] In Figure 4b, the peak centered at 529.16 eV, which is typical for the O 2− in TiO bonds in TiO 2 , [ 16,17 ] is clearly seen in the sample of TiO 2 powder, whereas suppressed in all samples of black TiO 2 QDs.…”

“…[ 16,17 ] In Figure 4b, the peak centered at 529.16 eV, which is typical for the O 2− in TiO bonds in TiO 2 , [ 16,17 ] is clearly seen in the sample of TiO 2 powder, whereas suppressed in all samples of black TiO 2 QDs. The additional 531–532 eV peaks observed in the black TiO 2 QDs are assigned to the OH bonds, [ 16,17 ] indicating that hydroxyl is formed through hydrogenation process. By further considering these peaks, the most shift of XPS spectra, both in the O 1 s and Ti 2p range, is found in the sample prepared by 0.4 m KCl.…”

Highly Efficient and Stable Perovskite Solar Cells Using an Effective Chelate‐Assisted Defect Passivation Strategy

“…Therefore, perovskite‐based materials have been considered as candidates for the construction of low‐cost solar cells. Notably, their power conversion efficiency (PCE) has rapidly increased from 3.8 % to the current record of 24.2 % over the past seven years . Consequently, perovskite solar cells (PSCs) are now considered to be the most favorable candidates for realizing high‐PCE and low‐cost solar cells with long‐term stability.…”

Low-Temperature Soft-Cover-Assisted Hydrolysis Deposition of Large-Scale TiO2 Layer for Efficient Perovskite Solar Modules

“…However, the high-temperature processing of the TiO 2 layer makes their manufacture more complex and hampers the development of lightweight and flexible substrates. To overcome this limitation, several deposition techniques to fabricate TiO 2 films at low temperatures have been successfully implemented, such as spin coating (SC) [ 11 – 13 ], atomic layer deposition (ALD) [ 14 , 15 ], sputtering [ 16 – 18 ], chemical bath deposition [ 19 , 20 ], and electron-beam evaporation [ 21 ].…”