Double-Layered PEDOT:PSS Films Inducing Strong Inversion Layers in Organic/Silicon Hybrid Heterojunction Solar Cells

Abstract

Poly­(3,4-ethylenedioxythiophene):poly­(styrenesulfonate) (PEDOT:PSS)/Si hybrid heterojunction solar cells (HHSCs) have attracted wide interests due to the potential high efficiency and low cost, but their open circuit voltage is limited. Here, double-layered PEDOT:PSS films (DL-PEDOT:PSS), high-work-function AI4083-type PEDOT:PSS (HW-PEDOT:PSS) used to combine with high-conductivity PH1000-type PEDOT:PSS (HC-PEDOT:PSS), were applied to induce strong inversion layers at the n-type silicon surface in PEDOT:PSS/Si HHSCs resulting in a quasi-p–n junction. Capacitance–voltage and minority carrier lifetime mapping demonstrates that the quasi-p–n junction was formed by strong inversion effect with large built-in voltage. The device with DL-PEDOT:PSS with 7 wt % EG added in HW-PEDOT:PSS (EG7-DL-PEDOT:PSS) exhibits a large open circuit voltage of 640 mV without any other modification, fill factor of 0.755, and power conversion efficiency of 12.69%. This suggests a promising method for the fabrication of low-cost and high-performance PEDOT:PSS/Si HHSCs, as well as a p-type passivated contact in the next-generation solar cells.

Performance‐Enhancing Approaches for PEDOT:PSS‐Si Hybrid Solar Cells

“…In 2018, Zhu et al first spin-coated a3 5nmthick layer of HW-PEDOT:PSS on an n-type silicon wafer with the goal of enhancing the built-in electric field and increasing the open-circuit voltage without increasing the series resistance.A dditionally,a55 nm thick layer of HC-PEDOT:PSS was spin-coated on top to maintain high conductivity.T he V OC of the HSC prepared by this doublelayer PEDOT:PSS method (DL-PEDOT:PSS) increased from 609 mV to 640 mV,a nd the PCE increased from 11.97 %t o1 2.69 %. [81] These results show that the V OC of the solar cell can be effectively improved by increasing the induced electric field in the intermediate interface and improving the work function of PEDOT:PSS.…”

“…Additionally, a 55 nm thick layer of HC‐PEDOT:PSS was spin‐coated on top to maintain high conductivity. The V OC of the HSC prepared by this double‐layer PEDOT:PSS method (DL‐PEDOT:PSS) increased from 609 mV to 640 mV, and the PCE increased from 11.97 % to 12.69 % [81] . These results show that the V OC of the solar cell can be effectively improved by increasing the induced electric field in the intermediate interface and improving the work function of PEDOT:PSS.…”

Conductive Hole‐Selective Passivating Contacts for Crystalline Silicon Solar Cells

“…Figure 3 a shows the C −2 − V plots at a signal frequency of 20 kHz for the PEDOT:Nafion passivated contact solar cells. Here, C is the capacitance of the device, C −2 is linear with the applied voltage, and the intercept corresponds to the built‐in potential according to Equation (2): [ 49 ] where V bi is the built‐in potential, V is the applied voltage, A is the device area, e is the electric charge, ε r is the relative dielectric constant, ε 0 is the permittivity of a vacuum, and N D is the concentration of the donor impurity. The device with a conductive passivation PEDOT:Nafion contact in the [C+P] region shows a higher built‐in potential than that with pristine PEDOT:PSS.…”

Strategien zur Steigerung der Leistung von PEDOT:PSS/Si‐Hybrid‐Solarzellen

“…[80] Die zwei gängigsten PEDOT:PSS-Arten sind das PH1000 69 % verbesserten PCE-Wert. [81] Diese Ergebnisse belegen, dass sich der V OC -Wert einer Solarzelle dadurch effektiv verbessern lässt, dass in der Zwischengrenzfläche ein stärkeres elektrisches Feld induziert und die PEDOT:PSS-Austrittsarbeit verbessert wird.…”