Recently, the electron transport layer (ETL) has become one of the key components for high-performance perovskite solar cell (PSC). This study is motivated by the nonreproducible performance of ETL made of spin coated SnO2 applied to a PSC. We made a comparative study between tin oxide deposited by atomic layer deposition (ALD) or spin coating to be used as an ETL in N-I-P PSC. 15 nm-thick Tin oxide thin films were deposited by ALD using tetrakisdimethylanmiotin (TDMASn) and using reactant ozone at 120 °C. PSC using ALD SnO2 as ETL showed a maximum efficiency of 18.97 %, and PSC using spin coated SnO2 showed a maximum efficiency of 18.46 %. This is because the short circuit current (Jsc) of PSC using the ALD SnO2 layer was 0.75 mA/cm2 higher than that of the spin coated SnO2. This result can be attributed to the fact that the electron transfer distance from the perovskite is constant due to the thickness uniformity of ALD SnO2. Therefore ALD SnO2 is a candidate as a ETL for use in PSC vacuum deposition.

This study compares the characteristics of a compact TiO2 (c-TiO2) powdery film, which is used as the electron transport layer (ETL) of perovskite solar cells, based on the manufacturing method. Additionally, its efficiency is measured by applying it to a carbon electrode solar cell. Spin-coating and spray methods are compared, and spraybased c-TiO2 exhibits superior optical properties. Furthermore, surface analysis by scanning electron microscopy (SEM) and atomic force microscopy (AFM) exhibits the excellent surface properties of spray-based TiO2. The photoelectric conversion efficiency (PCE) is 14.31% when applied to planar perovskite solar cells based on metal electrodes. Finally, carbon nanotube (CNT) film electrode-based solar cells exhibits a 76% PCE compared with that of metal electrodebased solar cells, providing the possibility of commercialization.

Orthorhombic DyMnO3 films are fabricated epitaxially on Nb-1.0 wt%-doped SrTiO3 single crystal substrates using pulsed laser deposition technique. The structure of the deposited DyMnO3 films is studied by X-ray diffraction, and the epitaxial relationship between the film and the substrate is determined. The electrical transport properties reveal the diodelike rectifying behaviors in the all-perovskite oxide junctions over a wide temperature range (100 ~ 340 K). The forward current is exponentially related to the forward bias voltage, and the extracted ideality factors show distinct transport mechanisms in high and low positive regions. The leakage current increases with increasing reverse bias voltage, and the breakdown voltage decreases with decrease temperature, a consequence of tunneling effects because the leakage current at low temperature is larger than that at high temperature. The determined built-in potentials are 0.37 V in the low bias region, and 0.11 V in the high bias region, respectively. The results show the importance of temperature and applied bias in determining the electrical transport characteristics of all-perovskite oxide heterostructures.