Biosensor, biosensor array and device

A biosensor, comprising:

• a stretchable substrate,
• a pixel defining layer on the stretchable substrate, the pixel defining layer including
• a first pixel defining layer defining a first opening extending through a thickness of the first pixel defining layer, and
• a second pixel defining layer defining a second opening extending through
• a thickness of the second pixel defining layer,
• a photo-detecting element at least partially in the first opening, and
• a first light emitting element at least partially in the second opening,
• wherein an area of the first pixel defining layer in a plane parallel to an in-plane direction of the stretchable substrate is about 2 times to about 25 times an area of the first opening in the plane parallel to the in-plane direction of the stretchable substrate.