Multi-junction light energy conversion element, device comprising the same, and fabrication method of SnZn2N2

A light energy conversion device, comprising:

• a light energy conversion element;
• a first electrode;
• and
• a second electrode,
• wherein the light energy conversion element, consisting of:
• a first light energy conversion layer as a single layer containing SrZn2N2;
• a second light energy conversion layer containing an light energy conversion material;
• and
• a joint layer provided between the first light energy conversion layer and the second light energy conversion layer,
• wherein the light energy conversion material has a narrower band gap than the SrZn2N2,
• the first light energy conversion layer of the light energy conversion element is present between the second light energy conversion layer of the light energy conversion element and the second electrode,
• the second light energy conversion layer of the light energy conversion element is present between the first light energy conversion layer of the light energy conversion element and the first electrode, and
• the second electrode is an electric conductor having a transparency such that light travels through the second electrode.