Solution-Processed Environmentally Friendly Ag2S Colloidal Quantum Dot Solar Cells with Broad Spectral Absorption

Abstract

A facile heat-up synthesis route is used to synthesize environmentally friendly Ag 2 S colloidal quantum dots (CQDs) that are applied as light absorbing material in solid state p-i-n junction solar cell devices. The as-synthesized Ag 2 S CQDs have an average size of around 3.5 nm and exhibit broad light absorption covering ultraviolet, visible, and near infrared wavelength regions. The solar cell devices are constructed with a device architecture of FTO/TiO 2 /Ag 2 S CQDs/hole transport material (HTM) /Au using a solution-processed approach. Different HTMs, N2,N2,N2 ,N2 ,N7,N7,N7 ,N7 -octakis(4-methoxyphenyl)-9,9 -spirobi(9H-fluorene)-2,2 ,7,7 tetramine (spiro-OMeTAD), poly(3-hexylthiophene-2,5-diyl) (P3HT), and poly((2,3-bis(3-octyloxyphenyl)-5,8-quinoxalinediyl)-2,5-thiophenediyl) TQ1 are studied for maximizing the device photovoltaic performance. The solar cell device with P3HT as a hole transport material gives the highest performance and the solar cell exhibit broad spectral absorption. These results indicate that Ag 2 S CQD have high potential for utilization as environmentally friendly light absorbing materials for solar cell application and that the hole transport material is critical to maximize the solar cell photovoltaic performance.

Hot‐Injection Synthesized Ag2S Quantum Dots with Broad Light Absorption and High Stability for Solar Cell Applications

“…The highest V OC in this work was 0.3 V, which is considerably lower than the maximum theoretical possible voltage for this material considering the band gap of around 1 eV, and the V OC was also lower compared to some other Ag 2 S solar cells published previously, see table S1 ,. The voltage loss for solar cells made with 4 CQD layers and larger losses for the thicker solar cells may indicate presence of defects.…”

“…Figure (f) shows the J–V curve of the 4‐layered device under illumination and in dark. The efficiencies of the best devices were compared with previously published Ag 2 S solar cells, most of which use Ag 2 S QDs or CQDs as a photo‐absorber, see table S1 ,. The devices made in this work show higher performance than previous studies, mainly due to relatively high current and fill factor.…”

“…Other quantum dot (QD) and Ag 2 S CQD solar cells that has been published show a range of different device structures. These structure include the aforementioned QDSSCs, as well as bulk heterojunctions or using a heat‐up synthesis, see Table S1. The open circuit voltage in all of the devices shown is low compared to other CQD materials ,.…”

Size‐Tunable Synthesis of Colloidal Silver Sulfide Nanocrystals for Solution‐Processed Photovoltaic Applications

“…Recently, Öberg et al. utilized Ag 2 S QDs as a light absorbing material in solution processed solar cells with a p‐i‐n heterojunction architecture with improved open circuit voltage and achieved PCE of 0.34% . Following similar approach of highly conducting network of 0D‐1D hybrid of QDs:CNT, Hu et al.…”

Fabrication and Luminescent Properties of Zn–Cu–In–S/ZnS Quantum Dot Films under UV Excitation

“…During fluorescence stimulation, quantum dots are excited by radiation of specific energy and emit in different wavelengths, depending on their size [3][4][5]. Their excellent chemical and physical properties, such as the high energy conversion efficiency, the high extinction coefficient, tunable emitting wavelength, the broad excitation spectrum, and the resistance to photobleaching have attracted the interest of the scientific community providing quite impressive results [6][7][8][9][10][11][12]. QDs are 20 times brighter and 100 times more stable than traditional fluorescent indicators [13].…”