Interdigitated back contact silicon heterojunction solar cell and the effect of front surface passivation

Abstract

This letter reports interdigitated back contact silicon heterojunction (IBC-SHJ) solar cells which combine the performance benefits of both back contact and heterojunction technologies while reducing their limitations. Low temperature (<200°C) deposited p- and n-type amorphous silicon used to form interdigitated heteroemitter and contacts in the rear preserves substrate lifetime while minimizes optical losses in the front. The IBC-SHJ structure is ideal for diagnosing surface passivation quality, which is analyzed and measured by internal quantum efficiency and minority carrier lifetime measurements. Initial cells have independently confirmed efficiency of 11.8% under AM1.5 illumination. Simulations indicate efficiencies greater than 20% after optimization.

Damage at hydrogenated amorphous/crystalline silicon interfaces by indium tin oxide overlayer sputtering

“…Subsequent curing ($190 C for a few minutes) after screen printing the metal grid front electrode brings the finished-device V oc almost fully back up to the initial implied-V oc . These results confirm that TCO sputtering damages the a-Si:H/c-Si interface in SHJ structures, 8,9 but that most of the damage is recovered by low-temperature annealing. In this paper, we first discuss the origin of the sputter damage.…”

a-Si:H/µc-Si:H tandem junction based photocathodes with high open-circuit voltage for efficient hydrogen production

“…The buffer layer at the n-i interface presumably acts as a defect passivation layer and reduces interface recombination, as already reported for heterojunction solar cells. 34,35 The best high voltage/high current tradeoff was provided by the a-Si:H/lc-Si:H tandem cell constituted of a 650 nm thick lc-Si:H bottom cell with a 20 nm buffer layer and a 250 nm thick a-Si:H top cell (cell C in Table I), which promoted over 1.5 V and 10.0 mA/cm 2 with 11.0% conversion efficiency. Furthermore, this tandem cell had a total thickness below 1 lm, accentuating its low-cost production and potential high stability against light-induced degradation.…”

Optimization of interdigitated back contact silicon heterojunction solar cells by two-dimensional numerical simulation

“…Hence front surface passivation is especially important for the IBC-SHJ cell. In later simulations, the front SRV value is chosen as 80 cm/s to simulate experimental results [1], unless otherwise stated.…”

“…A schematic diagram of the structure of an IBC-SHJ solar cell used for the numerical simulation is shown in Figure 1, and a detailed discussion of the device is given in reference [1]. A 2.5 Ω•cm n-type c-Si wafer (300 μm) is passivated with SiN x (75 nm) at the front surface.…”

“…An interdigitated back contact silicon heterojunction (IBC-SHJ) solar cell was proposed recently [1]. The IBC-SHJ combines the advantages of the interdigitated back contact (IBC) [2] and silicon heterojunction [3] solar cells.…”