Microstructures, optical and photoelectric conversion properties of spherical silicon solar cells with anti-reflection SnO_x:F thin films

Abstract

The microstructures and optical and photoelectric conversion properties of spherical silicon (Si) solar cells were investigated and discussed. The surface of the spherical Si with a pn junction provided high crystallinity, and the lattice constant of the center of Si spheres is larger than that of the surface, which would be due to the lattice distortion by defect structures at the center of Si. The conversion efficiencies of spherical Si solar cells coated with SnO x :F anti-reflection thin films were improved by annealing. The optical absorption and fluorescence of the solar cells increased, and the lattice constants of SnO x :F anti-reflection layers decreased after annealing. The mechanisms of chemical reactions at the Si/metal interface were also discussed.

Construction and characterization of spherical Si solar cells combined with SiC electric power inverter

“…Flexible, light solar cells were also manufactured using silicon spheres with a diameter of ~1 mm with a pn junction [21]. The spherical Si solar cells are one of the candidates for the portable electric source.…”

Construction and evaluation of photovoltaic power generation and power storage system using SiC field-effect transistor inverter

“…Consumption of Si can be reduced for the use of spherical Si solar cells, compared with conventional crystal Si solar cells [15][16][17][18][19][20][21][22][23][24]. Flexible and light solar cells were also manufactured using silicon spheres with a diameter of ~1 mm with a pn junction at the sphere surface [24][25][26][27].…”

“…Flexible and light solar cells were also manufactured using silicon spheres with a diameter of ~1 mm with a pn junction at the sphere surface [24][25][26][27]. The spherical Si solar cells are one of the candidates for the portable electric source.…”

“…The purpose of the present work is to construct and characterize photovoltaic power storage systems using spherical Si solar cells, maximum power point tracking (MPPT) charge controller, lithium-ion battery and a direct current-alternating current (DC-AC) inverter using SiC field-effect transistor (FET), considering self-standing, portable emergency power sources with low electric power ranges of ~100 W. The SiC-FET devices were introduced in the DC-AC converter [14], which was connected with the Li ion batteries. Since spherical Si panels are lighter and more flexible compared with ordinary flat Si solar panels [24,27], the spherical Si solar cells were selected as the power sources in the present work. To accumulate the generated electricity effectively, MPPT and Li ion batteries were also connected with the present system.…”

Evaluation of photovoltaic power generation system using spherical silicon solar cells and SiC-FET inverter

“…Spherical Si solar cells are a new type solar cell, and are composed of Si spheres with a diameter of ~1 mm with a pn junction [6][7][8][9][10][11][12][13][14], which can reduce the consumption of Si compared with crystalline Si solar cells. In our previous work, spherical Si solar cell systems combined with a direct current-alternating current (DC-AC) inverter using SiC field-effect transistor (FET) were constructed [15].…”