Silicotungstate, a Potential
Electron Transporting Layer for Low-Temperature Perovskite Solar Cells
Yoon Ho Choi
Hyun Bin Kim
In Seok Yang
Sang Do Sung
Young Sik Choi
Jeongho Kim
Wan In Lee
10.1021/acsami.7b05146.s001
https://acs.figshare.com/articles/journal_contribution/Silicotungstate_a_Potential_Electron_Transporting_Layer_for_Low-Temperature_Perovskite_Solar_Cells/5226340
Thin
films of a heteropolytungstate, lithium silicotungstate (Li<sub>4</sub>SiW<sub>12</sub>O<sub>40</sub>, termed Li-ST), prepared by a solution
process at low temperature, were successfully applied as electron
transporting layer (ETL) of planar-type perovskite solar cells (PSCs).
Dense and uniform Li-ST films were prepared on FTO glass by depositing
a thin Li-ST buffer layer, followed by coating of a main Li-ST layer.
The film thickness was controlled by varying the number of coating
cycles, consisting of spin-coating and thermal treatment at 150 °C.
In particular, by employing 60 nm-thick Li-ST layer obtained by two
cycles of coating, the fabricated CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> PSC device demonstrates the photovoltaic conversion efficiency
(PCE) of 14.26% with <i>J</i><sub>SC</sub> of 22.16 mA cm<sup>–2</sup>, <i>V</i><sub>OC</sub> of 0.993 mV and
FF of 64.81%. The obtained PCE is significantly higher than that of
the PSC employing a TiO<sub>2</sub> layer processed at the same temperature
(PCE = 12.27%). Spectroscopic analyses by time-resolved photoluminescence
and pulsed light-induced transient measurement of photocurrent indicate
that the Li-ST layer collects electrons from CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> more efficiently and also exhibits longer
electron lifetime than the TiO<sub>2</sub> layer thermally treated
at 150 °C. Thus, Li-ST is considered to be a promising ETL material
that can be applied for the fabrication of flexible PSC devices.
2017-07-12 00:00:00
Li 4 SiW 12 O 40
CH 3 NH 3 PbI 3 PSC device
electron
OC
TiO 2 layer
FF
PCE
uniform Li-ST films
photovoltaic conversion efficiency
FTO
ETL
Li-ST layer
Low-Temperature Perovskite Solar Cells
60 nm-thick Li-ST layer
coating
CH 3 NH 3 PbI 3
Li-ST buffer layer