693184 event 1791582757 1791582817 <![CDATA[Ph.D. Dissertation Defense - Jingwei Yang]]> Title:  High Performance Wavelength Selective Organic Photodiodes

Committee:

Dr. Bernard Kippelen, ECE, Chair, Advisor

Dr. Juan-Pablo Correa-Baena, MSE, Co-Advisor

Dr. Azadeh Ansari, ECE

Dr. Stephen Ralph, ECE

Dr. Ajeet Rohatgi, ECE

Dr. Natalie Stingelin, MSE

]]> This dissertation presents the design, optimization, and experimental realization of organic photodiodes (OPDs) that emulate the spectral and angular sensitivities of the human eye. Broadband organic absorbers are integrated with metal–dielectric multilayer (MDM) filters to reproduce photopic, scotopic, and melanopic response functions within a wide field of view comparable to human binocular vision. These devices target human-centric applications, including integrative lighting, bright light therapy, and display systems optimized for human perception. Following an overview of organic semiconductors, OPDs, and wavelength-selective detection technologies, MDM structures comprising alternating Ag and Al₂O₃ layers were selected to address the limited tunability and angular tolerance of existing structural filters. MDM structures were integrated with broadband OPDs in top- and bottom-illuminated architectures and optimized using measured optical constants and transfer-matrix modeling. Optimization minimized the mean squared error (MSE) between calculated photoactive-layer absorptance and target human sensitivity functions. Optimized designs achieved MSE below 0.02 at normal incidence and below 0.04 at incidence angles up to 60° for all three targets. Bottom-illuminated melanopic MDM-OPDs were fabricated and characterized, retaining over 50% of their normal-incidence spectral overlap with the melanopic function within a ±60° field of view. MDM integration preserved electronic performance, with low dark current density, comparable noise levels, and detectivities on the order of 10¹⁰ Jones relative to broadband reference OPDs. This work establishes a materials-to-systems framework linking optical modeling, thin-film processing, and device characterization to human eye–inspired photodetection. The demonstrated MDM-OPDs provide a potential route toward scalable multispectral sensors supporting real-time spectral feedback, color calibration, and regulation tailored to human spectral and angular sensitivities, laying the groundwork for human-centered optoelectronic applications that support wellbeing.

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