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A Circular 3D-Printing Economy Enabled by Photon Upconversion


Precourt Pioneering Project

Awarded in the focus area of re-inventing plastics and their lifecycle of use.



The 3D-printing market is growing at a dizzying pace, and it is predicted that over 10% of all manufactured products will be 3D printed within 10 years. Approximately 30% of bulk 3D-printed material is immediately discarded after fabrication, as most 3D prints require support structures to realize complex form factors. Currently, leftover plastic from 3D printing can only be recycled using expensive, specialized equipment for melting and extrusion. These recycling processes do not regenerate the original resin, and “new” prints generated from recycled resins typically exhibit inferior mechanical properties.

Project Goal

The overarching goal of this research is to reduce plastic waste from three-dimensional (3D) printing processes by developing a reusable 3D printing resin that can be printed, bulk erased, and re-printed over numerous cycles. This technology will be enabled by utilizing ‘print’ and ‘erase’ chemistry triggered by distinct wavelengths of light and will take advantage of upconverting nanocapsules to utilize low-energy photons to excite these processes. This will simplify the 3D-printing process by allowing deep light penetration into a sample and will reduce the materials costs of this technology.

Tasks and Timeline

The team will generate prints from recycled resin that have comparable physical properties to those of prints from fresh resin. This goal will be accomplished through three specific aims:
• Design and characterize fresh and recycled 3D-printing resins,
• Improve the quality and durability of the upconverting nanocapsules
• Engineer an integrated photochemical system that enables a circular 3D-printing economy.


Team Members

Dan Congreve is an Assistant Professor in the Department of Electrical Engineering at Stanford University. Prior to Stanford, Dan was a Rowland Fellow at the Rowland Institute at Harvard University. His research focuses on engineering nanomaterials and optoelectronic devices to solve challenging problems in fields including photovoltaics, light emission, and 3D printing.

Yan Xia is an Associate Professor of Chemistry at Stanford University. His research combines catalysis, organic and polymer chemistry, and a range of advanced characterizations to create, control, and study novel (macro)molecular structures and organic materials with tailored conformations, nanostructures, properties, and functions. These new soft materials have interesting and unusual properties/functions for applications in energy-efficient molecular separations, sustainable plastics, electronics, and therapeutics.

Danielle Mai is an Assistant Professor of Chemical Engineering at Stanford University. Danielle’s research aims to engineer functional biomaterials and to enhance fundamental understanding of soft matter physics. The Mai Lab integrates precise molecular design with multi-scale experimental characterization to generate polymers with tunable mechanics, stimuli-responsive behavior, and self-healing properties.

Tracy H. Schloemer is a postdoctoral scholar in the department of Electrical Engineering at Stanford University under Prof. Dan Congreve. Her current research focuses on the control and application of triplet fusion upconversion in complex soft matter-based systems. She earned her Ph.D. in applied chemistry from the Colorado School of Mines in 2019, where she focused on organic semiconductor design for improved operational durability of perovskite solar cells under Professor Alan Sellinger and in collaboration with the National Renewable Energy Lab

Mike Burroughs is a Postdoctoral Scholar in the Department of Chemical Engineering at Stanford University. His research interests include the molecular design of polymers to engineer sustainable soft materials. During his Ph.D. at UC Santa Barbara, he focused on understanding flow instabilities and the nonlinear rheology of entangled polymer liquids

Qi Zhou received her Honors B.S. degree in Materials and Nanoscience from Beijing Jiaotong University and University of Waterloo, where she had multiple research experience on moisture-induced nanogenerators (under Prof. Norman Zhou) and ultrastable polymeric glasses (under Prof. James Forrest). As a M.S. student in Materials Science and Engineering at Stanford, Qi joined Prof. Dan Congreve’s group and is currently working on upconversion nanocapsules and their applications in volumetric 3D printing.