With the rapid need
for new kinds of portable and wearable electronics,
we must look to develop flexible, small-volume, and high-performance
supercapacitors that can be easily produced and stored in a sustainable
way. An integrated system simultaneously converting recyclable energy
to electricity and storing energy is sought after. Here we report
photovoltaic energy conversion and storage integrated micro-supercapacitors
(MSCs) with asymmetric, flexible, and all-solid-state performances
constructed from thousands of close-packed upconverting nanoparticles
(UCNPs) via an emulsion-based self-assembly process using oleic acid
(OA)-capped upconverting nanoparticles. The carbonated-UCNPs supraparticles
(CSPs) are further coated with polypyrrole (PPy) to improve their
electrochemical performance. Such a design can develop CSPs@PPy as
electrode materials with high gravimetric capacitance, 308.6 F g
–1
at 0.6 A g
–1
. The fabricated MSCs
exhibit excellent areal capacitance,
C
s
= 21.8 mF cm
–2
at 0.36 A cm
–2
and
E
= 0.00684 mWh cm
–2
, and
have superior flexibility and cycling ability. The MSC devices have
a sensitive near-infrared ray (NIR) photoelectrical response capability,
which can capture the NIR of sunlight to convert it into electrical
energy and store the electric energy due to an excellent capacitive
performance. We propose a method for multifunctional integration of
energy conversion and storage, and provide future research directions
and potential applications of self-powered flexible wearable photonic
electronics.