In the field of perovskite solar cells, the contact angle of solutions influences device performance in multiple aspects:

For the perovskite layer: Precursor solutions with smaller contact angles spread better on the substrate, facilitating the formation of uniform perovskite films and reducing defects such as pinholes.

For charge transport layers (hole transport layers shown in the PPT): Excessively large contact angles on charge transport layers prevent the perovskite solution from fully wetting the interface, leading to poor interfacial contact and increased series resistance.

While large contact angles can reduce water penetration and delay perovskite decomposition, a balance must be struck with charge transport compatibility.

The ellipsometer module is a non-destructive characterization technique that analyzes material optical properties (e.g., refractive index, extinction coefficient) and structural parameters (e.g., thickness, roughness) by measuring changes in the amplitude ratio and phase difference of reflected polarized light. In perovskite solar cell research, ellipsometers are critical for optimizing film quality, interface design, and device performance, commonly used to test optical parameters, thickness, and roughness of perovskite film layers, transparent conductive layers, etc.

For perovskite layers: Refractive indices and extinction coefficients obtained by the ellipsometer module reflect the material's optical bandgap, crystalline quality, and light absorption characteristics. Direct/indirect bandgaps can be deduced via Tauc Plot combined with ellipsometry data.

For transparent conductive layers: Optical coefficients can be obtained to help researchers adjust layer thickness and doping concentration based on device efficiency changes.

The sheet resistance test module is primarily used in perovskite solar cell research to evaluate the electrical conductivity, uniformity, and interfacial contact quality of films or functional layers, playing a critical role in optimizing device efficiency and stability.

Transparent conductive electrode (TCO) sheet resistance testing: Reflects the conductivity of ITO, FTO, IZO, and other transparent conductive substrates. The goal is to reduce sheet resistance to minimize series resistance and energy loss. For example, comparing the impact of different deposition processes (e.g., magnetron sputtering, chemical vapor deposition) on ITO sheet resistance to balance light transmittance and conductivity.

For charge transport layers: Measuring sheet resistance of ETLs (e.g., SnO₂, TiO₂) or HTLs (e.g., Spiro-OMeTAD, PTAA) can optimize doping concentration or thickness.

For large-area uniformity: Evaluating uniformity in slot-die coating, blade coating, and other large-area fabrication methods through multi-point sheet resistance testing.

Reflectance reflects the ability of photovoltaic cells and single-layer films to reflect light across different wavelength bands. Reducing overall reflectance enhances light absorption. In perovskite solar cells, reflectance is typically evaluated alongside transmittance and absorbance to assess overall device performance, following the relationship: Absorption + Reflection + Transmission = 1.

Combined with external quantum efficiency (EQE) current integration curves, reflectance and absorbance curves allow researchers to clearly observe the device's light conversion capability across different bands, enabling timely adjustment of relevant film layer processes based on reflectance feedback to optimize device performance stepwise.