Multilayer Photodiode Detection for Higher Conversion Efficiency
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Solution Overview
Problem
Existing optical sensors using organic photodiodes (OPDs) face challenges in improving photoelectric conversion efficiency.
Innovation Solution
A detection device with a multilayered photodiode structure, comprising a first electrode, first and fourth buffer layers as hole transport layers, and second and third buffer layers as electron transport layers, stacked on a substrate, with the first and third electrodes electrically coupled, enhancing carrier transport and reducing recombination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional single-layer photodiode structure is used, then the device complexity is low, but the photoelectric conversion efficiency is insufficient
Solution Approach 1:
The photodiode is divided into multiple functional layers including first and second active layers, first and second buffer layers, and multiple electrodes. Each layer performs a specific function in carrier generation, transport, or collection, thereby improving photoelectric conversion efficiency through specialized functional segmentation while managing structural complexity.
Solution Approach 2:
The patent transitions from a conventional single-layer structure to a multilayer stacked configuration, adding vertical dimensionality to the photodiode design. This multi-layer architecture enables improved carrier separation and collection efficiency by creating multiple interfaces and transport pathways in the vertical direction.
2Loss of energy
If the travel distance of carriers is increased to improve collection, then carriers have more opportunities for recombination, reducing efficiency
Solution Approach 1:
The buffer layers are segmented into first and second buffer layers with different functionalities. The first buffer layer facilitates hole transport while the second buffer layer facilitates electron transport, creating specialized transport pathways that reduce carrier recombination by directing carriers efficiently toward their respective electrodes.
Solution Approach 2:
The buffer layers act as intermediary structures between the active layers and electrodes. These intermediary layers provide dedicated transport channels that mediate carrier movement, reducing direct recombination between electrons and holes by separating their transport pathways and facilitating efficient carrier collection.
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 multilayered structure improves photoelectric conversion efficiency by minimizing carrier recombination and optimizing the travel distance of carriers, leading to enhanced detection performance.
Implementation Method 1
Each of the first buffer layer and the fourth buffer layer is a hole transport layer
Implementation Method 2
Each of the second buffer layer and the third buffer layer is an electron transport layer
Implementation Method 3
optical sensors capable of detecting fingerprint patterns and vascular patterns... in each of the photodiodes, for example, a lower electrode, an electron transport layer, an active layer, a hole transport layer, and an upper electrode are stacked
Data Source
AI summary
According to an aspect, a detection device includes: a substrate; and a plurality of photodiodes in each of which a first electrode, a first buffer layer, a lower active layer, a second buffer layer, a second electrode, a third buffer layer, an upper active layer, a fourth buffer layer, and a third electrode are stacked on the substrate in the order as listed. The first electrode and the third electrode of the photodiode are electrically coupled to each other. Each of the first buffer layer and the fourth buffer layer is one of a hole transport layer and an electron transport layer. Each of the second buffer layer and the third buffer layer is the other of the hole transport layer and the electron transport layer.