Amir Bahrami

The built-in potential (Vbi) is an important parameter in semiconductor devices, particularly in solar cells and other photovoltaic devices. It represents the potential difference that exists across the junction of two materials, typically the absorber layer and the electron transport layer (ETL) or the hole transport layer (HTL).

To identify the built-in potential value, you need to consider the energy band diagram of the device structure. The built-in potential can be calculated as the difference between the conduction band energy levels at the interface between the absorber and the ETL, and the interface between the absorber and the HTL, divided by the elementary charge (q).

Mathematically, the built-in potential can be expressed as:

```

Vbi = (EC_Abs/ETL - EC_Abs/HTL) / q

```

Where:

- `EC_Abs/ETL` is the conduction band energy level at the interface between the absorber and the ETL.

- `EC_Abs/HTL` is the conduction band energy level at the interface between the absorber and the HTL.

- `q` is the elementary charge (1.602 × 10^-19 C).

The key steps to identify the built-in potential value are as follows:

1. Understand the device structure: Identify the absorber layer, the ETL, and the HTL in the device.

2. Determine the energy band diagram: Construct the energy band diagram of the device, which shows the relative positions of the conduction band, valence band, and Fermi level for each layer.

3. Identify the conduction band energy levels: From the energy band diagram, locate the conduction band energy levels at the interface between the absorber and the ETL (`EC_Abs/ETL`), and the interface between the absorber and the HTL (`EC_Abs/HTL`).

4. Calculate the built-in potential: Use the formula `Vbi = (EC_Abs/ETL - EC_Abs/HTL) / q` to calculate the built-in potential value.

It's important to note that the built-in potential can be influenced by various factors, such as the materials used, doping concentrations, and interface properties. Therefore, the specific value of the built-in potential may vary depending on the device structure and the parameters of the individual layers.

good luck; partial credit ai

Mohammad Imam

Hi, thank you for your answer from AI.

But unfortunately, the values calculated in this way do not match the values reported in the articles.