Multiple Cation-Doped Perovskite for Solar Cell Stability
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Solution Overview
Problem
Perovskite compounds with multiple halide ions are prone to photoinduced phase separation when illuminated, leading to uneven band gap distribution and reduced photoelectric conversion efficiency (PCE) in solar cells.
Innovation Solution
A multiple cation-doped perovskite compound is developed, represented by the formula ABX3, where A includes cesium and formamidinium ions, B is a divalent cation, and X includes at least two different halide ions, without methylammonium ions. This compound is used as the absorption layer in a perovskite solar cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the perovskite compound contains multiple halide ions to widen the band gap and adjust absorption wavelength, then the band gap increases and absorption coverage improves, but photoinduced phase separation occurs leading to uneven band gap distribution and reduced PCE
Solution Approach 1:
The patent introduces a novel parameter - the doping of multiple cations (at least three different cations including Cs+, FA+, and others like MA+, Rb+, K+, or organic cations) into the perovskite structure. This compositional parameter change fundamentally alters the crystal lattice stability, preventing halide ion segregation while maintaining wide band gap and high absorption efficiency across 400-800 nm wavelength range
Solution Approach 2:
The patent creates a composite perovskite material by combining multiple cation types within the same crystal structure. This composite approach (mixing Cs+, FA+, and at least one other cation) produces a synergistic effect where the diverse cations work together to stabilize the lattice against photoinduced phase separation while maintaining the desired optical properties
2Adaptability or versatility
If multiple halide ions are used to achieve wide band gap, then the band gap widens to cover visible spectrum, but segregation of halide ions occurs under illumination causing photoinduced phase separation
Solution Approach 1:
The patent changes the compositional parameters by incorporating at least three different cations in specific ratios, which fundamentally alters the lattice dynamics and prevents halide ion migration and segregation under illumination, thereby maintaining phase stability while preserving wide absorption range
Solution Approach 2:
The multiple cations act as intermediaries that mediate between the different halide ions in the lattice. The presence of diverse cations creates a more uniform charge distribution and lattice strain, which prevents the segregation of halide ions and maintains compositional homogeneity throughout the material
3Reliability
If conventional silicon solar cell materials are used, then the technology is mature and reliable, but the raw material cost is high
Solution Approach 1:
The patent changes the material composition parameters by using abundant earth-element cations (Cs, FA, and others like Rb, K, or organic cations) combined with common halides, replacing expensive silicon with perovskite materials that have similar or superior photovoltaic properties but significantly lower raw material costs
Solution Approach 2:
The patent employs inexpensive perovskite materials with abundant earth elements as alternatives to costly silicon. The perovskite layer can be deposited as a thin film using low-cost solution processing techniques, making the solar cell economically viable despite the emerging technology status
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The multiple cation-doped perovskite compound effectively prevents photoinduced phase separation, enhances photoelectric conversion efficiency, and improves thermal stability of the solar cell, while maintaining a wide band gap for efficient light absorption.
Implementation Method 1
wavelength of absorption band of the perovskite compound may easily be adjusted to fall between 400 nm and 800 nm, which covers approximately an entire visible wavelength range
Implementation Method 2
further improving photoelectric conversion efficiency (PCE) of the perovskite compound to use as an absorption layer of a solar cell
Data Source
AI summary
A multiple cation-doped perovskite compound includes a perovskite represented by a formula of ABX3. A includes M1, M2, and M3. M1 represents a cation different from M2 and M3; M2 represents a cesium ion and M3 represents a formamidinium ion. B represents a divalent cation different from M1, M2, and M3. X includes at least two different halide ions. In addition, the perovskite compound is free from methylamine ion. A perovskite solar cell including the multiple cation-doped perovskite compound is also provided.