A band-gap-graded CZTSSe solar cell with 12.3% efficiency

Abstract

Using an appropriate SeS2/Se weight ratio, band gap grading was realized. By increasing the value of VOC through band gap grading in the depletion region, a record VOC deficit of 0.576 V and an efficiency of 12.3% were obtained.

Carrier transport and surface potential over phase variations in the surface and bulk of highly efficient Cu2ZnSn(S,Se)4 solar cells

“…As an antireflection coating, MgF 2 was deposited with a thickness of 100 to 110 nm by an electron beam evaporator. Detailed information of the process conditions and properties of the MgF 2 layers are available in an earlier report . The device parameters of the samples are shown in Table ; the total area of each sample was 0.185 cm 2 (with an active area of 0.179 cm 2 ).…”

“…Thus, the difference in efficiency between the total and active areas was less than 1%. The current‐voltage ( I–V ) characteristics were measured under the condition of a simulated air mass 1.5 global (AM 1.5 G) spectrum and an illumination of 100 mW/cm 2 (1 sun) using a solar simulator (Newport Co, model 94022A) …”

“…Although CZTSSe exhibits suitable optical and electrical properties for use as a light absorber in thin‐film solar cells, the highest power conversion efficiency (PCE) achieved for kesterite solar cells is only 12.6% (using a hydrazine‐based nonvacuum process) . Daegu Gyeongbuk Institute of Science and Technology (DGIST) attained a PCE of 12.3% by employing a vacuum deposition process (sputtering), and, more recently, they have reached a PCE of 12.5% using a Sn/Cu/Zn/Mo precursor stack and 12.6% . This study explores further improvements to CZTSSe thin‐film solar cells to compete with conventional thin‐film solar cells such as CdTe (22.1%) and Cu(In,Ga)Se 2 (CIGS) (22.9%) …”

“…Thus far, researchers have only managed to explain the current flow in the materials; the minority carrier can move into intragrains (IGs) to induce the expected band bending and obtain the surface current maps . Recently, CZTSSe thin‐film solar cells fabricated through vacuum deposition with pure‐metal precursor stacks have shown reasonably high efficiencies (even in metallic flexible substrates) . However, the secondary phases and defect states in kesterite thin films display varied and complex distributions, which limit the carrier transport effectiveness and PCE improvement .…”

Thin Film Solar Cells Based on Copper-Indiumgalium Selenide (Cigs) Materials Deposited by Electrochemical Techniques.

“…The Cu(In,Ga)(S,Se)2 ternary and quaternary semiconductor compounds are the most widely used absorption materials for photovoltaics applications is now well established, due to their unique structural and photoelectric properties [66,67]. At present, research on this class of materials has focused on IIIA, VIA compounds, such as CuInSe2, Cu(In, Ga)Se2, Cu(In,Ga)S2 and so on [68,69,70].…”