Pb-Free Double Perovskite SWIR Materials for Stable Solution Processing
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Solution Overview
Problem
Conventional short-wave infrared (SWIR) materials are expensive, toxic, small in size, unstable, and require complex fabrication processes, limiting their application in various imaging and sensing technologies.
Innovation Solution
Development of Pb-free double perovskite SWIR materials using a composition represented by Formula (I): A2BCD6, incorporating a nitrogen-containing compound, formed through a simplified process involving precursor solution dispersion and annealing on a substrate, which can include Cs2AgBiBr6, Cs2AgSbBr6, Cs2AgInCl6, Cs2CuBiBr6, or Cs2NaBiCl6, and utilizing chemical solution deposition techniques like spin coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional SWIR materials (InGaAs, HgCdTe, InSb, PbS, PbSe, Pb-based perovskites) are used, then SWIR imaging and sensing performance is achieved, but the materials are expensive, toxic, unstable, and require complex fabrication processes
Solution Approach 1:
The patent changes the compositional parameters by replacing toxic Pb-based perovskites with Pb-free double perovskite materials having the general formula A2BCD6. This compositional change maintains the desired SWIR optical properties while eliminating toxicity and improving stability. The use of environmentally friendly cations (Cs+, K+, Na+, Li+) and stable metal combinations (Ag, Cu, Au with Bi, Sb, In) fundamentally alters the material parameters to achieve both reliability and ease of manufacture
Solution Approach 2:
The invention employs composite material design by creating double perovskite structures with multiple cationic components (A and B sites) and anionic components (D sites). This composite approach allows tuning of optical and structural properties to achieve stable SWIR performance. The nitrogen-containing compound integration further enhances stability through passivation of surface defects and improvement of crystalline structure, resolving the contradiction between reliability and manufacturability
2Object-affected harmful factors
If conventional SWIR materials are used, then SWIR detection capability is achieved, but the materials are expensive and toxic
Solution Approach 1:
The patent converts the harmful effect of lead toxicity into a benefit by systematically replacing Pb2+ ions with non-toxic alternative cations (Cs+, K+, Na+, Li+) combined with stable metal pairs (Ag/Cu/Au and Bi/Sb/In). This substitution eliminates the harmful toxicological impact while maintaining or enhancing the structural stability and optical performance for SWIR applications, thereby converting a harmful material choice into a beneficial environmentally friendly solution
Solution Approach 2:
The invention adopts readily available, inexpensive precursors and environmentally benign materials that can be processed under mild conditions. The use of common cations and stable metal halides reduces material costs compared to rare or toxic conventional SWIR materials. The simplified solution processing and low-temperature annealing further reduce manufacturing expenses, making the material both affordable and stable
3Ease of manufacture
If conventional SWIR materials are used, then SWIR imaging performance is achieved, but the fabrication processes are complex
Solution Approach 1:
The patent replaces complex mechanical and high-energy fabrication processes with simple solution-based processing. The double perovskite materials can be synthesized and deposited from liquid precursor solutions using low-cost techniques such as spin-coating, dip-coating, or inkjet printing, followed by low-temperature annealing (300-500°C). This substitution of mechanical/thermal processing with chemical solution processing dramatically simplifies manufacturing while maintaining high film quality and crystalline structure
Solution Approach 2:
The invention changes the processing parameters by enabling low-temperature fabrication (300-500°C) compared to conventional high-temperature vacuum deposition or molecular beam epitaxy. The solution-processable nature of the double perovskite materials allows precise control of film thickness, uniformity, and morphology through simple parameters like spin-coating speed, annealing temperature, and precursor concentration, achieving high manufacturing precision with simplified processes
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 new SWIR materials are stable, toxicity-free, easy to fabricate, and cost-effective, offering broad absorbance from 500 nm to 2800 nm, suitable for applications in automobiles, remote sensing, vehicle control, automated inspection, surveillance, and environmental chemical analysis.
Implementation Method 1
The inclusion of a nitrogen-containing compound in the perovskite structure has been shown to passivate surface defects and improve the overall crystalline structure, leading to enhanced stability and SWIR performance
Implementation Method 2
annealing the dispersed precursor solution on the substrate by heating the substrate at an annealing temperature that is from about 100° C. to about 300° C. to form a film composition
Data Source
AI summary
Aspects of the present disclosure generally relate to short-wave infrared materials and to processes for making short-wave infrared materials. In an aspect, a composition is provided that includes: a nitrogen-containing compound or ion thereof; and a Pb-free double perovskite material. The composition can be utilized as a short-wave infrared material. The perovskite materials described herein and compositions thereof show improved stability and can be fabricated at lower costs.