Power conversion efficiency of 25.26% for silicon heterojunction solar cell with transition metal element doped indium oxide transparent conductive film as front electrode

Abstract

In this paper, to improve the power conversion efficiency (Eff) of silicon heterojunction (SHJ) solar cells, we developed the indium oxide doped with transition metal elements (IMO) as front transparent conductive oxide (TCO) layer combined with microcrystalline silicon (μ‐Si:H(n+)) for SHJ solar cell. The optical and electrical properties as well as structures of hydrogenated IMO (IMO:H) films were studied and compared to conventional indium tin oxide (ITO) film. Such IMO:H films have high carrier mobility over 70 cm2/V·s, high transmittance, and low free carrier absorption, which leads to a high short circuit current density exceeding 40 mA/cm2. In addition, the low sheet resistance and contact resistivity of the IMO:H films contribute to the high fill factor of the solar cell. The average Eff of solar cells with IMO:H + μ‐Si:H(n+) is improved by 0.4% compared with that of the solar cells with ITO + a‐Si:H(n+). Finally, a certified efficiency up to 25.26% (total area, 274.5 cm2) was achieved.

Achievement of 25.54% power conversion efficiency by optimization of current losses at the front side of silicon heterojunction solar cells

“…9 Shortly after this, they improved the PCE to 25.26% for their M6/166 mm wafer sized SHJ solar cells in their pilot production line, in collaboration with solar cell and module maker Huasun Energy. 10,15 At the time, this PCE value matched that achieved by LONGi's that the world's largest module supplier reported. 10,13 The most noteworthy feature that these SHJ solar cells have in common is that they contain n-type hydrogenated nanocrystalline silicon oxide (nc-SiO x :H) instead of a-Si:H(n) layers, which are used for charge carrier collection.…”

“…Recently, Suzhou Maxwell Technologies, a Chinese production equipment producer for the photovoltaic (PV) industry, claimed to have achieved efficiency of 25.05% for their M6/166 mm wafer sized SHJ solar cells from pilot production line, produced with their in‐house equipment, including cleaning and texturing, PECVD, PVD, screen printing, and LED annealing 9 . Shortly after this, they improved the PCE to 25.26% for their M6/166 mm wafer sized SHJ solar cells in their pilot production line, in collaboration with solar cell and module maker Huasun Energy 10,15 . At the time, this PCE value matched that achieved by LONGi's that the world's largest module supplier reported 10,13 .…”

“…For the IMO target, M is the abbreviation for titanium oxide (TiO 2 ), cerium oxide (CeO 2 ), and tantalum oxide (Ta 2 O 5 ) with the mass ratios of 0.22, 0.14, and 0.03 wt%. 15 The base vacuum pressure of the chamber was less than 2 Â 10 À4 Pa, and the pressure for the sputtering process was set as 0.78 Pa. All films were prepared under argon (Ar), oxygen (O 2 ), and argon-water (Ar-H 2 O) mixture gases. The Ar-H 2 O mixture gas was introduced by passing Ar gas through H 2 O.…”

“…Recently, Dong et alalso reported a TCO films by doping transition metal elements inIn 2 O 3 (IMO) as front electrode and made some achievements. However, due to the sputtering process in argon-hydrogen mixture, the mobility (72.5 cm 2 /VÁs) is moderate, and the carrier concentration is high, which makes the TCO less transparent 15.…”

High Mobility Hafnium and Hydrogen Co-Doped Indium Oxide Transparent Conductive Films and Application in High Efficiency Silicon Heterojunction Solar Cell

“…As the annealing temperature increases, both the transmission and reflection spectra change significantly due to the change in refractive index caused by the rise in crystallinity (Figure S3). 37 In order to eliminate the effect of reflection on transmission, the effective total transmittance (TTe) spectra are used instead of the transmission spectra to evaluate the optical properties of the IHfO:H films annealed at different temperatures, 38 as shown in Figure 9. TTe is defined as TTe = T…”