Tpp-ce6 is a mitochondria-targeting photosensitizer formed by binding chlorophyll e6 (Ce6) to triphenylphosphine (TPP) via an ester bond. TPP-Ce6 can produce ROS under light irradiation, especially singlet oxygen, which can induce oxidative stress, leading to mitochondrial dysfunction and apoptosis. TPP-Ce6 can be used in the study of mitochondria in apoptosis and energy metabolism as well as cancer therapy.