The　quasi　one-dimensional　layered　KP15　shows　in-plane　anisotropic　electrical/optical　properties　and　high　carrier　mobility.　In　this　work,　for　the　first　time,　its　electrical/optical　properties　are　studied　by　fabricating　phototransistors　based　on　mechanical　exfoliated　KP15　nanowires.　The　device　shows　high　specific　detectivity　(＞10(10)　Jones　throughout　the　visible　band　with　peak　value　＞　10(12)　Jones)　and　fast　response　time　(similar　to　10　ms,　shorter　than　most　photodetectors　based　on　2D　Mo　or　W　sulfides).　The　excellent　device　performance　suggests　KP15　as　a　new　candidate　material　for　photonic　and　optoelectronic　devices.　(C)　2020　Elsevier　B.V.　All　rights　reserved.